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Post by Night Ranger on Mar 25, 2015 20:01:24 GMT -5
I have a question about the Tram D201a BA board version 1. This board has the center pin removed from the series pass transistor. Why would Tram do this? Is the center pin connected to the back of the series pass transitor case? See the picture below. This is a picture I found on the Internet, but it shows the center pin clipped. Tram D201a BA board version 1 img809.imageshack.us/img809/3964/57cr.jpgFor the record a friend brought me a Tram D201a to repair. There is no 14.4 volts coming off his BA board. I just started digging in to it. UPDATE: Nevermind. I just found the datasheet. The collector on pin 2 is connected to the mounting base. Question answered. : ) 2n5295 datasheet pdf1.alldatasheet.com/datasheet-pdf/view/437700/ISC/2N5295.htmlThanks, Night Ranger |
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Sandbagger
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Post by Sandbagger on Mar 25, 2015 21:38:38 GMT -5
I have a question about the Tram D201a BA board version 1. This board has the center pin removed from the voltage regulator. Why would Tram do this? Is the center pin connected to the back of the regulator case? See the picture below. This is a picture I found on the Internet, but it shows the center pin clipped. Tram D201a BA board version 1 img809.imageshack.us/img809/3964/57cr.jpgFor the record a friend brought me a Tram D201a to repair. There is no 14.4 volts coming off his BA board. I just started digging in to it. UPDATE: Nevermind. I just found the datasheet. The collector on pin 2 is connected to the mounting base. Question answered. : ) 2n5295 datasheet pdf1.alldatasheet.com/datasheet-pdf/view/437700/ISC/2N5295.htmlThanks, Night Ranger Be careful. If the 14V supply goes south on a D201a, it can fry the OP amp IC that drives the meter circuit. |
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Post by Night Ranger on Mar 25, 2015 22:08:37 GMT -5
I have a question about the Tram D201a BA board version 1. This board has the center pin removed from the voltage regulator. Why would Tram do this? Is the center pin connected to the back of the regulator case? See the picture below. This is a picture I found on the Internet, but it shows the center pin clipped. Tram D201a BA board version 1 img809.imageshack.us/img809/3964/57cr.jpgFor the record a friend brought me a Tram D201a to repair. There is no 14.4 volts coming off his BA board. I just started digging in to it. UPDATE: Nevermind. I just found the datasheet. The collector on pin 2 is connected to the mounting base. Question answered. : ) 2n5295 datasheet pdf1.alldatasheet.com/datasheet-pdf/view/437700/ISC/2N5295.htmlThanks, Night Ranger Be careful. If the 14V supply goes south on a D201a, it can fry the OP amp IC that drives the meter circuit. It may already be toast. The needle on the meter sits constantly in the middle of the display when the radio is turned on. These were the problems when it was brought to me; 1) Previous bozo put 20 amp fuse in 3 amp fuse holder. The 20 amp fuse was bent inside but not blown. 2) No receive 3) No transmit except for a carrier on sideband at about 27.900 MHz (self oscillation - fixed). 4) Gunk leaking out of the bottom of one of the main high voltage filter capacitors. 5) Black channel selector 6) Dead microphone element in D-104 (Fixed - replaced with D104m6b element) 7) I don't like the sound coming from the transformer, but that is probably due to high current draw from the dried out capacitors. 8) No 14.4 volts DC voltage coming from the BA board so everything powered by it is dead. The rectifier checks good, and there is AC from the transformer. I disconnected the 14.4 volt output supply to the other boards to make sure a short to ground further down the line was not pulling down the voltage. The 4 MHz VFO is working and the 5.8015 MHz fixed crystal tied to the tube oscillator works. I'm not sure it is worth fixing. It is not in the best condition cosmetically. Night Ranger |
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Sandbagger
Administrator/The Boss
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Post by Sandbagger on Mar 26, 2015 6:07:46 GMT -5
Be careful. If the 14V supply goes south on a D201a, it can fry the OP amp IC that drives the meter circuit. It may already be toast. The needle on the meter sits constantly in the middle of the display when the radio is turned on. These were the problems when it was brought to me; 1) Previous bozo put 20 amp fuse in 3 amp fuse holder. The 20 amp fuse was bent inside but not blown. 2) No receive 3) No transmit except for a carrier on sideband at about 27.900 MHz (self oscillation - fixed). 4) Gunk leaking out of the bottom of one of the main high voltage filter capacitors. 5) Black channel selector 6) Dead microphone element in D-104 (Fixed - replaced with D104m6b element) 7) I don't like the sound coming from the transformer, but that is probably due to high current draw from the dried out capacitors. 8) No 14.4 volts DC voltage coming from the BA board so everything powered by it is dead. The rectifier checks good, and there is AC from the transformer. I disconnected the 14.4 volt output supply to the other boards to make sure a short to ground further down the line was not pulling down the voltage. The 4 MHz VFO is working and the 5.8015 MHz fixed crystal tied to the tube oscillator works. I'm not sure it is worth fixing. It is not in the best condition cosmetically. Night Ranger I absolutely love the D201 series of Tram radios. But they really are high maintenance. So many things fail in that rig (mostly from heat), that the 100,000 mile overhaul should probably consist of replacing all electrolytic caps along with all 1 and 2 watt carbon resistors. You really won't get much if the 14.4 volt supply is dead. It powers all solid state components in the radio, including the crystal synthesizer oscillators and the Balanced modulator board. The black gunk coming out of one of the electrolytics is probably due to excessive heating from an internal short, which would also account for the odd sound from the transformer. And that's probably why the 3 amp fuse was replaced by a 20. |
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Post by BBB on Mar 26, 2015 13:50:17 GMT -5
So the 3 amp fuse holds?
20 amp fuse = Bad JU JU.
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Post by bill on Mar 27, 2015 11:47:01 GMT -5
Not all D201A's with the Black Crystal Selector Switch have / had problems... I have another D201A besides my Upgraded Grey Switch one that has a Black Switch... The Switch works perfectly, and I am NOT Gentle with it either... If that BA Board photo is the exact BA Board you have, it's Time for a Rebuild ! Capacitors and Resistors on it, for Sure ! ... OR, Buy an " Improved BA Board " from Nomad which would then allow one to use a Lesser Expensive 12 Volt Relay versus the 120 Volt used in the Tram, if one chooses... Other NOS Parts along with a Complete BA Board are available at Barkett Electronics too... Yes, Owning and Operating these Tube Radios can be expensive, but to Me, Worth it... What I found most Frustrating years ago, as a Tinkerer / Hobbyist, was Ordering Parts, Item by Item, in an Online Catalog ! If one gives themselves an Hourly Rate to Shop for Parts, it would be Expensive... TODAY, I notice a Fellow on EBay that offers " Restoration Kits " and has been expanding his Offerings... www.ebay.com/itm/TRAM-D201-D201A-Upgrade-Restoration-Kit-Capacitors-Resistors-Updated-/261810297815?pt=LH_DefaultDomain_0&hash=item3cf51c1bd7Here's a Relay, at a Cost Savings, compared to others I have seen www.ebay.com/itm/New-unopened-Tram-201A-Relay-/141613592630?pt=LH_DefaultDomain_0&hash=item20f8d3f036Here's a Radio for Sale, Serviced by Barkett Electronics... Read the Ad Description to Learn, How Expensive it can be, for a Restoration www.ebay.com/itm/TRAM-D-201A-BASE-RADIO-WITH-D-104-MIKE-BERKETT-RADIO-SERVICED-VERY-NICE-/121605884735?pt=LH_DefaultDomain_0&hash=item1c50468b3fIf one does not Consider their Radio, "Good Looking ", try Here to ask about a " Faceplate Overlay " ... I believe they Purchased " Deb's Decals " if anyone was Familiar with that name... They DO Sell one for the Tram, and more... www.gammaraygraphics.com/base-radios.htmlI have seen Photos, I believe also Posted here, of a Tram D201 / D201A with a Black Faceplate that looked Nice to Me... I imagine one could get ANY Color they choose ? If one did a SEARCH Here, using the Search Feature, one would find some Great Threads about the Radio... Nomad Radio, AKA; 2600 , Nomad , Chris, has Posted Many Restoration Articles and such for these Radios and More... Given the Radio's Age alone, it should be Totally Restored, in order to achieve any Reliability... Replace EVERY Electrolytic Capacitor, including the Multi-Section High Voltage Filter Capacitors... Replace a Couple Dozen Carbon Composition Resistors, with Metal Oxide ones of the Same Value, of a Higher Rating, basically Doubling the Watt Rating... This Eliminates close to 30 ? Suspect Components, due to Old Age... Do you have the Manual / Schematic ? The Manual is a Complete Service Manual, which is Great ! I seem to have FORGOTTEN more than I ever thought I knew, about the D201A... All My Equipment is " Packed-Up ", anticipating a Relocation... I am not a Technician, nor do I claim to be... 2600 or Nomad could stroll in here and set you Straight... Fixer or Alan at www.tubesplus.com could also... They know these Radios like the back of their Hand... Along with Greg Barkett... As far as the 14 Volts.... I think I remember reading, as someone had mentioned, an 8 Pin IC, I think U400 can get taken out... I forget the Cause of the Failure, but thought if U400 Failed, there would then be No 14 Volts in the Circuits... I believe I remember it was suggested to place a Plug-In IC Socket there, so if it ever happened again Replacement would be easier... ? I remember a Couple of Design Flaws were often mentioned... A 160 Volt Electrolytic Capacitor that SHOULD be a 450 Volt Part, mentioning if a certain Tube Failed, it could then put High Voltage into the Coax and possibly the Operator... There's a 1KV Disc Capacitor ? that should have been a 2KV Part, as another Tube Failure can take that 1KV Part out... Sorry, It's been a Number of Years since I Restored the D201A's I have and have Forgotten the Details ? |
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Post by bill on Mar 27, 2015 12:08:17 GMT -5
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Mar 27, 2015 15:47:59 GMT -5
Just an FYI, when you paste links to other forums, unless you are a member of that particular forum, chances are you will not be able to view the content contained in the link. |
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Post by BBB on Mar 27, 2015 15:52:20 GMT -5
I've tried to join that CB Tricks forum many times over the years but always get an error message saying "Sorry, registration is currently disabled" Anyone know what gives? Maybe I've been black listed as an instigator, haha. Or maybe it only responds to IE or Chrome. I'm using Firefox.
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Post by 2600 on Mar 28, 2015 0:24:11 GMT -5
New signups on that forum are currently turned off.
Every time the owner turns it back on, hundreds of spammers sign up. An admin has to approve each new signup manually.
The time it takes was a killer, and the labor to police the spammer-signup tsunami not so easy to come by.
I'd love to see a solution to this dilemma.
73
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Post by bill on Mar 28, 2015 8:54:23 GMT -5
My apologies... I had read at that Website a Thread that had said, Visitors could USE CBTricks' , just COULD NOT POST ? Apparently, that was / is Incorrect ?
I am also sorry that I distracted 2600's Attention to the Problem with your Radio he could easily Assist One to Solve... I have created more Harm, than Good here...
Perhaps it was Wrong of Me to attempt to Cross-Post Information, or Direct One away from this Group in order to Gain Information ?
My only intentions were to try to be Helpful.... Now I am not so sure...
Time to get Geared-Up to spend my Free Time, Fishing... I can't get Myself in too much Trouble in Solitude...
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Mar 28, 2015 9:21:50 GMT -5
New signups on that forum are currently turned off. Every time the owner turns it back on, hundreds of spammers sign up. An admin has to approve each new signup manually. The time it takes was a killer, and the labor to police the spammer-signup tsunami not so easy to come by. I'd love to see a solution to this dilemma. 73 Spammers sign up here as well, although not to the level that CBTricks has. I have a "Once and done" policy on spammers. Repeat offenders get their IP blocked. But if I had to deal with 10 or 20 of them in a day's time, it would become a problem...... Even going through the motion of approving every new signup would be extra work. |
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