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Post by capn357 on Dec 2, 2017 23:29:27 GMT -5
On another superhawkwss6 note not related to the D300, superhawkwss6 is the current high bidder for a 23 channel Tram d201 being sold for parts at a whopping $1225! (ebay listing 222734211859).
I'd sure like to know what his plan is this time. Will he turn around and try to sell this radio for $2,500? From other posts on other forums, I've heard where he's previously bought stuff, then claimed it wasn't as advertised, received a refund and then sent back different equipment (i.e. same model number, but different serial number in worse condition). However, I don't see how he could do that this time since the listing in question clearly states that the radio has not been tested and that the buyer should assume that it is not working.
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Post by capn357 on Nov 27, 2017 18:44:10 GMT -5
Alright, so a quick scan of Hawk's recent feedback reveals that a single buyer has purchased the following items in the past week!: item price date nitro 300 amp $749 9/22/2017 cobra 2000 $1400 9/24/2017 tram d300 $1200 9/26/2017 tram d300 speaker $250 9/26/2017 palamar 350 $800 9/19/2017 browning mk4a $2500 9/19/2017 total $6899 over span of seven days I'd say either Hawk has found the most gullible buyer on Ebay with the most money to burn ever, or there is some sort of scam going on here. UPDATE: The subject system (Tram D300 + speaker) has just resurfaced on Ebay under listing number 112658586039. Here is a short synopsis of the chronology: 9/1/2017: Tram D300 (sn ending in 87) + speaker sold by me to "hawk" for total of $470 (ebay listing 332357427138) 9/26/2017: Tram D300 (sn ending in 87) + speaker sold by "hawk" for total of $1,450 (ebay listings 263209388149 and 263231257448) to "o***o ( 330)" <- Ebay purposely scrambled buyer identity as shown in "hawk's" feedback. This listing included a bunch of made up history about the rig as previously documented. 11/27/2017: Tram D300 (sn ending in 87) + speaker for sale now by Comoal(330) on Ebay listing 112658586039 for buy it now price of $900.00 . It doesn't take a rocket scientist to conclude that Comoal(330) is "o***o(330)" shown in hawk's feedback not only as the purchaser of the subject tram D300+speaker, but also several other items in late September. Assuming that is the case, then two things immediately pop out as interesting to me:
1. While his buy it now price of $900.00 is still outrageously high, it is still $450.00 below what he supposedly paid hawk for this rig two months ago. 2. I now know the identity of the person that ostensibly paid hawk $6,899 for various items (see top of this post) in the span of seven days in September. If the purchase half of these transactions were on the up and up (meaning Comoal is an unwitting participant in "hawk's" BS listing practices), then I'd conclude that Comoal has really been taken to the cleaners; so much so that I don't have the heart to break the news to him.
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Post by capn357 on Oct 23, 2017 11:53:31 GMT -5
I "think" those are all of the variants, but I'm sure if I'm wrong, someone will let me know.
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Post by capn357 on Oct 19, 2017 8:20:43 GMT -5
That looks "very nice-a" (ala the French guy in the castle in Monty Python and the Holy Grail).
You could always make up some fantastic story about it like Superhawk does and list it on Ebay for $3,000 and see what happens.
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Post by capn357 on Oct 1, 2017 19:26:26 GMT -5
Alright, so a quick scan of Hawk's recent feedback reveals that a single buyer has purchased the following items in the past week!:
item price date
nitro 300 amp $749 9/22/2017
cobra 2000 $1400 9/24/2017
tram d300 $1200 9/26/2017
tram d300 speaker $250 9/26/2017
palamar 350 $800 9/19/2017
browning mk4a $2500 9/19/2017
total $6899 over span of seven days
I'd say either Hawk has found the most gullible buyer on Ebay with the most money to burn ever, or there is some sort of scam going on here.
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Post by capn357 on Sept 27, 2017 10:58:17 GMT -5
So a couple of things: First, if it is to be believed, Hawk did actually sell that Tram d300 on 9/26 for $1,200 and then almost immediately sold a spare speaker for a Tram D300 for another $250! Is it possible that one person purchased both so that he could have a MONO stereo Tram D300 system for $1,450? Additionally, I found a link on the Worldwide DX forum where people have shared their experiences with this guy. A couple claimed he purchased stuff from them, then later filed a claim stating that what he received was not as described, received a refund and then sent back a different (worse) unit to the seller. I guess I should consider myself lucky that that didn't happen to me. At least my original sale did go through (apparently) although he did use a credit card with his paypal payment (of course) which cost me some money.
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Post by capn357 on Sept 25, 2017 17:41:10 GMT -5
I'm reasonably sure that Ebay doesn't accept reports questioning the accuracy of the description and/or condition of a listing, which I can understand (they'd be inundated with this type of report otherwise).
However, nothing stopped me from creating a listing providing a test report summarizing the result of receiver and transmitter tests I performed on the unit just prior to selling it. Now any prospective buyers can see that this unit was in the hands of a member of "the public" for the past 10 years.
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Post by capn357 on Sept 16, 2017 9:11:15 GMT -5
I had a back and forth with Sandbagger a while back about a fellow that goes by SuperHawk listing old radios at outrageously high prices on Ebay. Well now I have personal knowledge of one of the items Superhawk is currently selling and can say for certain that he is exaggerating the condition of this radio. He recently purchased a Tram D300 that I owned for the past 10 years that I listed on Ebay a few weeks ago. While the radio is in extremely good condition and did come with the original packaging, it was most certainly "used" at best.. However, Superhawk has re-listed the radio (at $1,200 by the way) and specified the condition as "New (other)" with a title of "TRAM D-300 AM/SSB IN BOX / VERY 1ST MADE #87 / X TRAM ENGINNER RIG / CB HISTORY. He goes on to state that the radio was never sold to the public and was a "PROMO radio". Even if he has some irrefutable knowledge that this particular unit, by virtue of the serial number, was never sold by tram through the normal sales channels, it did for sure make its way out to "the public" at least once via Ebay which is how I purchased it ten years ago. His description is at best misleading and at worst a complete fabrication.
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Post by capn357 on May 27, 2017 22:45:51 GMT -5
I have a Motorola CB 555 that is exhibiting a weird (to me) problem on transmit. Here's the deal. If you power the radio on and key the mike, it will initially transmit at extremely low power (like 54 dB below where it should be). However, if I keep keying and unkeying the mike, the transmit power will eventually work it's way up (not all at once) finally topping out at a good solid 4 watt carrier. Once it reaches the 4 watt output, it will continue to reliably output at 4 watts on subsequent mike keys for as long as I've had the patience to sit there and run through the process. However, if I stop keying the mike and just leave the radio on for a while (say 30 minutes) and then come back to it and key the mike, I'm back at the extremely low power output mode. Just like before, if I continue to key and unkey the mike, it will eventually work it's way up to the 4 watt output and is steady at that point so long as I'm periodically keying the mike (like you would be if you were having a real conversation).
Has anyone ever heard of any radio behaving this way? Any thoughts on what would cause such behavior?
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Post by capn357 on May 18, 2017 11:39:54 GMT -5
Our database says we had the service manual 25 years ago. But where it may be is less clear. I'll make a note to look for it, but it might be after the Dayton Hamvention. 74 Great! Thanks.
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Post by capn357 on May 15, 2017 16:51:32 GMT -5
Does anyone know where I can obtain either an official Motorola service manual for the CM540 or alternatively, a good schematic for same? I obtained an old SAMs excerpt for this unit, but the schematic is of poor quality (especially the microphone section, which is what I need).
I'm unpleasantly amazed at what appears to be the absolute dirth of information online about this radio.
(I have a microphone that won't modulate and I've been unable to diagnose or fix the problem. No pinout information and no luck figuring anything out poking around with my multimeter (practically everything shows up as 13.6V when reverenced to the outside sleeve of the micrphone, which makes no sense to me)).
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Post by capn357 on May 9, 2017 16:45:09 GMT -5
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Post by capn357 on May 8, 2017 21:41:17 GMT -5
And then there's Superhawk. He thinks every radio he sells is rare and worth 3 times what it's actually worth. I just ran across a very normal looking (condition-wise) 23 channel Tram D201 (PC board based) on ebay listed for $989 by guess who?
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Post by capn357 on Apr 7, 2017 16:45:58 GMT -5
So I picked up an old Motorola CM540 mobile. Cosmetically, it's great and receives well. However, there is no modulation on transmit. I don't (yet) have a schematic so I haven't yet tried to really figure out if the problem is related to the microphone or to the radio other than trying to use the PA system of the radio with the same microphone, and verifying that that doesn't work either. There is a ton of functionality built into this microphone (channel up/down, channel revert, power mic gain) which translates into a crazy 10-pin interface.
Anyone out there familiar with this rig? Any advice would be appreciated.
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Post by capn357 on Mar 23, 2017 17:14:23 GMT -5
Given my lack of knowledge, I like questions, as it helps me learn more... I try to figure out the problem(s) and SHOULD wait for the more knowledgeable to Answer and then compare mine to theirs, as at times I am wrong Just like previously by not adding the Bridge Rectifiers to determine the Frequency of the Hum... No big deal though as far as being corrected, as it is ALL part of Learning to me... Don't beat yourself to death about asking questions as you seem to have a good amount of knowledge enough to do the Restoration... It reads like you have the desire to become more involved as you invested in Test Equipment... You must find some pleasure in doing it, or you probably wouldn't have made it this far with the Radio... People here are good people possessing a lot of knowledge and helping others is the reason the Group exists... Closer to your neck of the woods out of the 3 Technicians mentioned are, in no particular order, Nomad Radio in Louisville, Kentucky www.nomadradio.com Phone Number shown here www.facebook.com/pages/Nomad-Radio/163763540309430 and Greg Barkett in Trinity, Alabama www.goldeneagleradios.com as Alan is in Parker City, Indiana www.tubesplus.com ... In your search, you might find that some Techs might not offer, Ship-In, Ship-Out Service though as Shipping Companies can be brutal... No offense to any Tech, but as was mentioned a Restoration is not going to be cheap... Not sure what the going Labor Rate is, but I've heard it can take 4-1/2 Hours more or less, plus Parts, plus Shipping both ways... One has to Pack the Radio carefully if Shipping is involved... Shipping in itself is not cheap and it comes with risk of Damage or worse... One could always get on the Radio and ask other Operators where they have their work done too locally... One could also possibly find an Amateur Radio Operator Club nearby to visit on their Meeting Night and ask about any Tech who belongs... Just suggesting some options... Thanks. I've made some inquiries.
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Post by capn357 on Mar 21, 2017 17:15:24 GMT -5
So, the real miracle is that it worked as well as it did until the hum appeared. The hum you are hearing is probably not 60 Hz, but 120 Hz. The full-wave bridge rectifier that feeds high voltage to the tubes produces two "peaks" to charge the filter caps for each 1/60th of a second 'cycle' of the 60 Hz AC power that gets rectified. The hum you hear should be one octave above the sound you get from a halfway plugged-in electric-guitar cord. The power-supply filter capacitors were not meant to last more than ten or fifteen years, let alone 40-plus. Good chance that this is a low-mileage radio, and that's why it took so long for this symptom to appear. You can approach this problem two ways. First, you can check the capacitors and replace only the ones that are bad. Good chance that a close look at the underside of C5, the taller of the two aluminum "can" capacitors will reveal some light brown or black schmoo that has leaked out of it. And it can go completely bad without showing any external sign. If you don't have a way to test capacitors, this will make it tougher to identify parts that look good but don't work any more. And even if you test every one in the radio and replace just the ones that flunk, this will become a game that I call "Electronic Whack-a-Mole". One or two at a time the rest of the electrolytic caps that test good today will fail down the line. Not a matter of "if" but of "when". The fact that the volume control won't affect what you hear points to C5. Doesn't mean that it's the only one that's failed. Textbook term for this is "supply ripple", because of how it looks on a 'scope screen. Ripple that's feeding into the audio circuits between the volume control and the speaker won't be affected by the volume control. You can approach this any way you want. A commercial-quality repair would be to "re-cap" the radio as some folks call it. I call it the 100,000-mile tuneup, and replace every electrolytic cap in the radio, along with other wear-and-tear parts that we know from experience are the cause of common faults. And if you want to make a 1974 car your daily driver, total up all the belts, hoses, seals, gaskets and bearings you would need to replace. The D201 will be cheaper to restore than a car. But 40-plus years takes its toll even if the mileage is low. 73 Indeed it is likely 120 Hz as you say. Certainly there is some amount of 120 Hz that is still making it through to the keyed audio because I can see that on the spectrum analyzer display. It's a good ways down from the main audio, but it is there nonetheless. I hope I'm not causing frustration with my constant questions and my "whack a mole" approach. I've much appreciated the insight and there is no doubt that the advice has helped me successfully beat the moles down thus far however slow and inefficient I may be. That notwithstanding, I might be interested in having a professional restore at least the hand-wired D201 that I recently acquired. Please pardon my further ignorance, but I don't know who does this kind of restoration professionally. Do you guys have any recommendations in this regard? I'm in the Atlanta area if that makes any difference. If
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Post by capn357 on Mar 21, 2017 15:25:28 GMT -5
Is the Radio still using all the original Components ? Such as the Electrolytic Capacitors ? Such as the 2 Multi-Section ones which are for the Power Supply ? Who's job are to Filter the 60 Hertz Alternating Current " Hum "... Mainly, it is quite common for people to perform what is referred to as a 100,000 Mile Tune-Up by Nomad... Due to Old Age Components... I believe it involves replacing EVERY Electrolytic Capacitor in the Radio, as the Electrolyte Fluid within them dries out over time... Carbon Composition Resistors are said to not age well either and lose their Resistance, which will increase Voltages... One's eyes are a good piece of Test Equipment as one often sees some of these Carbon Comp. Resistors which appear to be much Darker in Color, often making it hard to read the Identifying Stripes that are Painted on them... Others appear to have "Blisters" on them, as if something is oozing out from within... Sure signs these Resistors are bad... One can Test these Resistors in Circuit, measuring as close to the Resistor Body as possible to determine if they are within Tolerance... One can refer to the Schematic and Test Circuit Voltages too to see if they are up to Specifications... It's Ying and Yang... Every Component is dependent on each other in order for the Radio to perform as it was Designed... Yes, Owning and Operating these Radios can be expensive, especially if one is paying someone to do the work... No Technician here, nor do I claim to be... Just a Hobbyist Tinkerer... Just echoing the Words of others when it comes to Vintage Electronics in general... The Radio is full of Components never designed to last this long... To gain reliability, a Restoration is in order... It is quite common that an initial failure can cause other failures within the Circuit, that is referred to a Domino Effect, one thing fails then another then another... Performing a 100,000 Mile Tune-Up eliminates a multitude of well-known Problematic Components prone to failure... Failure due to Old Age... Of course you are right; I'm sure the radio could benefit from a wholesale cap and power resistor replacement. I just thought because of the way this failed so suddenly that someone might have an idea of what might bring that on....plus I was aggravated that this happened so soon after I finally figured out that other issue I've been chasing for weeks. I understand that those high voltage filter caps go south, but I would have thought that they typically gradually go south (from leakage) as opposed to the instantaneous failure that I experienced. So based on Sandbagger's feedback, I first swapped out several of the tubes, but this didn't uncover anything or rectify the problem. Then I figured I'd try out this brand new (new to me, actually I purchased a demo unit) LCR meter and check the filter caps. I was skeptical of how well this would be able to check caps "in situ", but I have the benefit of having two other D201's available so I figured I could always check any reading that looked suspect against the other units to see if anything was out of the ordinary. Lo and behold I found that one of the 10uF caps on C624 (one of the big silver canisters) showed 36K Ohms as opposed to ~10 uF. I happened to have a 10uF 450 VDC cap on hand that I just alligator clipped in parallel to see if it would make a difference (I know it's not optimum, but I was just experimenting to see if it made any improvement). Sure enough, the hum decreased significantly, although not entirely. I guess I know now that a cap can fail instantaneously. I'll probably eventually restore this particular unit although I haven't decided whether to have someone do it for me or tackle it myself. If I do it myself, it'll take me so long that the first caps I replace will probably need replacing again by the time I replace the last ones Thanks for the responses.
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Post by capn357 on Mar 20, 2017 23:10:36 GMT -5
So I've been fiddling with this hand-wired D201 for weeks now trying to figure out what failed or what I broke to cause the manual receive (and transmit) to stop working. Tonight, within 10 minutes of finally finding and solving that problem (short on terminal block that effectively shorted pin 7 and pin 8 circuits on V302B), a loud audio hum suddenly appeared from the speaker. It was as if someone [waiting to kill my joyful mood] flipped a switch. This hum has the following characteristics:
1. The volume of the hum is constant and independent of the radio volume. 2. When powering on the unit, the hum does not appear until the tubes have warmed up (more specifically, not until after the meter goes through its gyrations and just before the receive audio comes alive). 3. As I said before, this hum came out of nowhere and went from 0 to 60 (literally) instantaneously.
Any idea what would cause such a step function audio problem?
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Post by capn357 on Mar 12, 2017 21:21:47 GMT -5
Still no joy figuring out what I did to break the manual receive on this unit, but thinking back to what I may have "hit" during my cleaning of the unit, I started looking at the large red coil (L301 I believe) connected to the manual tune capacitor. I don't see anything wrong there (i.e. the two wires seem to still be connected), but I can get the manual receive to at least make a popping noise if I tap on the top of that coil. Is there more to that coil than meets the eye or is it as dirt simple as it appears? Anyone ever seen that fail?
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Post by capn357 on Mar 9, 2017 0:19:21 GMT -5
Upon further analysis, the demodulated baseband signal emanating from this D201 is decidedly asymmetrical in the positive direction. That explains the increased distortion level as compared to the other two Trams. I'm wondering if this was a purposeful aspect of the audio board modifications that were performed by our tech or an undesirable artifact. I can't see why he would have done this purposely given the high carrier level and relatively low modulation percentage.
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Post by capn357 on Mar 8, 2017 15:23:17 GMT -5
WOW... Sounds pretty Technical to me... Sure, I suppose everyone wants the best Output, but what difference does it or will it make to a Crappy Receiver of the Signal ? I don't know a lot admittedly... Here's the most Technical Video of a Tram's performance that I know of... www.youtube.com/watch?v=pYGYxbXZrcII'm not sure if it falls in line with anything you are doing, or not... Bill, thanks for providing that link. After watching that video, the weakness I see in that analysis is that it didn't include any modulation; that is where all of the distortion I'm speaking of and that I've measured comes into play. The unmodulated carrier is indeed pristine just as can be seen on that video. He should have put the spectrum analyzer in "max hold" mode, keyed the mike, and exclaimed, "Break o-n-e n-i-n-e! How 'bout that Rubber Hose, you got a copy?" into the mic. That's when the splatter, if any, would occur.
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Post by capn357 on Mar 8, 2017 12:46:02 GMT -5
I hooked up some test equipment in order to measure, among other things, the distortion level on the transmitted audio at 1KHz. When the test equipment registered 7% distortion on the first of my three D201s that I tested, I thought, "Holy smoke, that's high! There's no way that's right!" I immediately went to the manual only to find that the specification for the audio output is "4 watts at 10% T.H.D." The other two d201s I have produce similar results. Admittedly, all of my units are in need of the "100,000 mile service" (to borrow a phrase from Nomad). I'm curious to know what distortion levels you guys have seen or have been able to achieve with these units. You have to take the term "distortion" in context. At the core, the definition of distortion is any deviation from the original signal. But tube amplifiers have an inherent distortion that makes the audio sound "warmer" or "more rich". So having 7% distortion may not be a bad thing. Distortion is also hard to quantify without accurate test equipment. Y-e-a-h, that's kind of what I figured. Two worlds are colliding for me now: My teenage CB days operating our tube based D201 and my subsequent adult life as an engineer. More recently, when considering and evaluating stereo audio equipment, I've flatly dismissed subjective evaluation in favor of hard measurement results. I've found myself put off by the un-quantifiable characterizations of some audiophiles such as "punch", "presence", "life", and yes, "warmth". Instead, I always took the positions of "give me equipment that produces the waveform as it was originally recorded" and "if it can't be measured, it isn't real". Not surprisingly, all of my stereo equipment is solid state based and I'm sure lacks warmth, life, punch, and presence That said, I think I can make an exception now when it comes to CB's. I suppose I can go along with the idea of "coloring" the audio here since there is nothing particularly interesting about maintaining the absolute fidelity of someone yapping on the radio. Still, I am interested to know what type of distortion is typical and/or achievable with these units. For my part, I'm using an HP 8903B Audio Analyzer to supply the audio to the mic input of the D201 (2mV is what I chose), and then using an HP 8568B as a tuned receiver to demodulate the transmitted signal from the D201 (8568 tuned to carrier frequency and set to zero span, linear scale). I then feed the demodulated signal (i.e. video output of 8568B) into the 8903B. The 8903B measures the frequency, amplitude, and distortion level (either percentage or amplitude) of the demodulated signal. The 8903B provides no insight into where, in frequency, the distortion is, just the extent (amplitude) of it. I can certainly get a sense of the where from viewing the 8568 results in a more traditional swept frequency mode. One potential weakness of my current setup is the way in which I'm coupling the output from the D201 into the input of the 8568 spectrum analyzer. I've simply inserted a paper clip into the center conductor of the input of the 8568 to serve as a bad antenna to pick up the leakage from the D201 that is transmitting into a dummy load. This "works" and serves to address the incompatibility of the 4-25 Watt direct output of the D201 (depending upon which one I'm using) and the 1 Watt maximum input allowed on the 8568. Ideally, it would be nice to have a 40 dB directional coupler that I could insert inline to pick off the signal directly, but I don't have one of those presently. Incidentally, I also used this basic setup as described to characterize the distortion produced by the combination of a D201 + old Elkin 6 tube amplifier. Here again, the Elkin is all original and I'm sure is in need of some cap replacement at a minimum. At the low output setting the of Elkin, I get about 80-90 Watts on the Bird 43 and about 15-18% distortion on the 8903B (again, the input to the Elkin coming from the D201 contains about 6% distortion level). On the high setting of the Elkin, the Bird registers somewhere north of 150, but the distortion goes through the roof at 35% or higher and the video trace on the 8568 no longer resembles a sine wave. My next alteration to the test setup is to put a speaker or headphones in place of the 8903B analyzer so that i can hear all of that good (and bad) distortion. In school, I always took a liking to electromagnetics and radio wave propagation, but never liked or really understood the electronic design part of it. Consequently, I'm very comfortable analyzing and evaluating the modulated radio wave, but have little clue how exactly it is produced and what affects the performance of it, at least not down below the block diagram level. I really wish I could look at a schematic and clearly understand what the circuit was doing and how it would behave strictly from a glance at the topology and values of the discrete components, but I cannot. These recent experiments with my old radios are forcing me to confront my weakness in electronic design and I greatly appreciate the help and insight you and others have provided along those lines.
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Post by capn357 on Mar 8, 2017 8:54:12 GMT -5
I hooked up some test equipment in order to measure, among other things, the distortion level on the transmitted audio at 1KHz. When the test equipment registered 7% distortion on the first of my three D201s that I tested, I thought, "Holy smoke, that's high! There's no way that's right!" I immediately went to the manual only to find that the specification for the audio output is "4 watts at 10% T.H.D."
The other two d201s I have produce similar results. Admittedly, all of my units are in need of the "100,000 mile service" (to borrow a phrase from Nomad).
I'm curious to know what distortion levels you guys have seen or have been able to achieve with these units.
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Post by capn357 on Mar 8, 2017 8:25:38 GMT -5
Alright, so let's presume my rig is undermodulated. Suppose I wanted to back down the carrier power to a level where my Audio section (however modified) can more adequately modulate the carrier. Can that be done without a wholesale change of components or without completely detuning the RF final section? (I'd like to just add a volume pot to the input of V700:D). Yes, you can drop he RF power by simply doing what Tram did in the first place with the original tube, by dropping the plate voltage to the final tube. The original circuit used a total of 4.2K (7-10 watt resistors) between the B+ and the modulation transformer leading to the final. You probably only have to drop the power down to between 15 and 20 watts and you should be able to regain 100% positive modulation. Alright, so I acquired some test resources and confirmed that the 25 watt carrier was indeed undermodulated. Moreover, when looking at the unit itself I saw that as part of this modification, R642 and R643 were completely removed (I guess jumpering these two wasn't good enough for our tech as he must have decided he wanted to retain a few items for his trouble). He also re-provisioned the 4 uF capacitor (C628) and used it as part of his funky modification to the audio board. So I purchased a 50 watt 10K pot and a 100 uF capacitor (I saw some reference to somebody's mods for the d201 that suggested the 100 uF as a replacement for the standard 4 uF) to insert back into the circuit in place of R642, R643, and C628, respectively. This "worked" in so much as I can now adjust the pot and vary the carrier output power anywhere from a watt or two to about 28 watts. I haven't yet figured out all of the details of the modifications this tech made to the audio board as part of the overall 6146 mod, but I don't think he accomplished much of anything with those mods other than adding a bunch of distortion to the audio output. I have to back the carrier output level all of the way down to near the rated output of 4 watts in order to achieve full modulation with an acceptable (6-7%) distortion level. About the only good thing I can think of to say about this modification at this point is that it didn't appear to cause any unique heat-related issues to my unit. As I've stated previously, the ONLY board that shows any signs of heat damage is the upper right corner of the BA board; everything else looks great and I used to leave this radio on for many hours (if not days) straight back in the stone ages. Other than that, all I'm left with at this point is a bit of a Frankenstein monster that I no longer know how to align properly.
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Post by capn357 on Mar 8, 2017 7:51:41 GMT -5
I would start at pin 6 of V302. You should have about 400 Volts DC when the manual oscillator is off, and around 110 Volts DC when the VFO is activated. Two 22k 2 Watt resistors R319 and R320 are in series to drop 400 Volts down to 110 when the VFO is running. If you can't get 100 Volts or so, one of these two resistors may have failed. Mileage is a factor. We replace those two resistors without testing them first as part of a routine 100,000-mile tuneup. The carbon-composition, or "chocolate fudge" resistors are not terribly reliable. If what you see is 400 Volts ALL the time, in XTL and MAN mode both, this suggests that the VFO is not being activated. This is done by completing the circuit to ground from L302, by the yellow wire on pin 11 of S4. S4 closes from pin 11 to pin 10 only in MAN mode. The orange wire on pin 10 would normally go to pin 8 of the relay, which allows the VFO to activate only for receive. The dirt-simplest mod to transmit with the VFO is to ground the orange wire from S4 pin 10, and to break the red/white wire at pin 12 of the SYN board's connector. A two-pole toggle switch is all that's needed for this one. Breaking the wire to SYN board pin 12 shuts down the 4 MHz crystals. The VFO output takes the place of those four crystals. Grounding the orange wire on S4 pin 10 activates the VFO all the time that MAN is selected, both for receive and transmit. The dirt-simplest mod to the orange and red/white wires has some drawbacks, but it's the most-popular mod for this version of the D201. There are more-complicated methods, meant to improve the lineup between your transmit and your receive frequency. If other wires have been disturbed, one of those mods may have been used. We are assuming, of course, that V302 is in good shape and not the cause of the problem. Maybe. Oh, and this schematic is correct for the "hand-wired" radio with the VOX feature. www.cbtricks.com/radios/tram/d201/graphics/tram_d201_sch.pdf73 I finally got the opportunity to try out this procedure. In Xstal mode I measure approximately 430 volts on pin 6 and in manual mode that drops to approximately 68 volts, so "something" is happening there at least. Both are measured with a very cheesy craftsman multimeter that certainly leaves much to be desired. Speaking of that cheesy meter, it measures R319 and R320 (in circuit) at approximately 26K ohms each as opposed to the rated 22K ohms.
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Post by capn357 on Feb 27, 2017 21:44:52 GMT -5
I would start at pin 6 of V302. You should have about 400 Volts DC when the manual oscillator is off, and around 110 Volts DC when the VFO is activated. Two 22k 2 Watt resistors R319 and R320 are in series to drop 400 Volts down to 110 when the VFO is running. If you can't get 100 Volts or so, one of these two resistors may have failed. Mileage is a factor. We replace those two resistors without testing them first as part of a routine 100,000-mile tuneup. The carbon-composition, or "chocolate fudge" resistors are not terribly reliable. If what you see is 400 Volts ALL the time, in XTL and MAN mode both, this suggests that the VFO is not being activated. This is done by completing the circuit to ground from L302, by the yellow wire on pin 11 of S4. S4 closes from pin 11 to pin 10 only in MAN mode. The orange wire on pin 10 would normally go to pin 8 of the relay, which allows the VFO to activate only for receive. The dirt-simplest mod to transmit with the VFO is to ground the orange wire from S4 pin 10, and to break the red/white wire at pin 12 of the SYN board's connector. A two-pole toggle switch is all that's needed for this one. Breaking the wire to SYN board pin 12 shuts down the 4 MHz crystals. The VFO output takes the place of those four crystals. Grounding the orange wire on S4 pin 10 activates the VFO all the time that MAN is selected, both for receive and transmit. The dirt-simplest mod to the orange and red/white wires has some drawbacks, but it's the most-popular mod for this version of the D201. There are more-complicated methods, meant to improve the lineup between your transmit and your receive frequency. If other wires have been disturbed, one of those mods may have been used. We are assuming, of course, that V302 is in good shape and not the cause of the problem. Maybe. Oh, and this schematic is correct for the "hand-wired" radio with the VOX feature. www.cbtricks.com/radios/tram/d201/graphics/tram_d201_sch.pdf73 Thanks a lot for taking the time to detail this process; I had hit a bit of a wall with my own attempts to troubleshoot this. I'm going to give this a shot first thing when I get back home from taveling.
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Post by capn357 on Feb 27, 2017 18:22:54 GMT -5
(small chuckle) Makes me wonder how many of the tubes will still be in the socket when it arrives at its new home. The tube sockets used in the circuit-board D201 radios sucked big time. Tram was having trouble with tubes shaking out of the sockets when the radios were shipped any way other than Grayhound Bus. The radio would arrive with the fragments of broken tubes rattling around inside when the buyer received it. The fix? LOC-TITE!!! Yep. The factory would apply the stuff to the tube pins when they assembled the radio. Just pulling a tube out of the socket to test it would take a fifty or hundred-pound pull. It would come out wth a loud "POW!", to reveal the dusty brown residue of Loc-Tite on the pins. The sad part was plugging the tube back into the socket. It would roll around loose, with little or no friction against the tube's pins. Crackle noises, and an intermittent radio were the result. Until the loose socket was replaced. Gotta wonder what sort of a sound it will make if you shake the carton when the buyer receives it. Tinkle, jingle? Box of Rocks? 73 Wow! Was that a practice they started when they knew the end was near? Otherwise, I can't imagine doing such a thing if they thought they were actually going to be a viable business for any extended period of time. I'm reasonably certain my original PC board based D201 (23 channel) didn't have any loctite unless it disintegrated and disappeared over the last 40 years (there's no evidence of it now).
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Post by capn357 on Feb 26, 2017 12:03:37 GMT -5
Finally won for $995.
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Post by capn357 on Feb 26, 2017 0:13:01 GMT -5
Sounds crazy but have you checked the relay? No I haven't checked the relay. I was originally thinking that since the unit works in both receive and transmit in crystal mode that that would indicate that the relay is working, but I guess that only proves that some of the "channels" of the relay work, yes? Actually, not only is the manual receive dead, but the unit also doesn't transmit (according to bird wattmeter) when the manual/crystal selector is in the manual position.
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Post by capn357 on Feb 25, 2017 22:06:55 GMT -5
Is anyone familiar with an Xmit on VFO mod for the D201 that involved removing all connections to pins 1 & 3 of selector S4 (crystal/manual selector)? If so, I could really use a description of that complete modification so that I can figure out what the heck is going on with my handwired D201, which has such a mod.
I'm trying to track down a problem with my manual receive and finding that I can't rely upon the standard troubleshooting and/or schematic because of this mod.
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