|
Post by Night Ranger on May 28, 2015 10:59:06 GMT -5
I found out why the VCO becomes wobbly at it's top range and then loses lock around 27.54x MHz. The voltage output from the programmable divider is maxed out and stops increasing after 27.54x MHz. The voltage in on Vdd (pin 1 ) is 5.36 volts and the max voltage from the "PD out" (pin 5) at 27.54x MHz is 5.35 volts. It's out of juice! That also explains why adjusting the VCO coil did not fix it. Night Ranger Adjusting the coil SHOULD fix it, as that is what you are compensating for. The VCO has a voltage range between about .5V to about 5V give or take. The voltage is dependent on the frequency of the oscillator, which is set by the LC values of the varactor diode and the tank coil. Move the coil value, and the VCO voltage moves the capacitance of the varactor to maintain frequency. Likewise, if you are hitting the edges of the VCO voltage ranges (either high or low), you can move the coil value to shift the VCO back into the usable range. Try it. Put your volt meter on the VCO voltage on one of your higher channels, and then adjust the coil and the voltage should swing up or down depending on which way you turn it. You should probably be turning it counterclockwise to decrease the inductance, which should shift frequency higher. If you can no longer compensate the frequency, then you've probably ran out of adjustment. I've never had that problem with the later 02a boards, but I can't comment on the 01's I went back and played with the VCO coil again (T-101). I was able to get it up to 27.655 MHz on channel selector 23 with programming pins 10 and 11 forced high. That matches the BCD code; 27.655 MHz - 24.965 MHz = VCO 2.690 MHz VCO 2. 6 9 MHz BCD 1 110 1001 I lost VCO lock on channel 1 at first, but I may have found the setting that allows the whole range. It is definitely at it's maxed VCO range as is. If channel 1 loses lock due to temperature changes I will sacrifice the higher channel to get stability on channel 1. If I can extend the VCO range that still leaves forcing programming pin 12 high for a BCD code of 1 111 1001 which should be VCO down mix frequency 2.790 MHz. 24.965 MHz + 2.790 MHz = 27.755 MHz. "1 000 0000" (CB channel 1) may be as low as it can go without reverting to straight binary mode. Night Ranger
|
|
|
Post by Night Ranger on May 28, 2015 14:50:37 GMT -5
Here comes some 1970s techno nostalgia....
If I balance the channel selector between...
1) 3 and 2 I get 26.995 MHz (3a) 2) 11 and 12 I get 27.095 MHz (11a) 3) 19 and 18 I get 27.195 MHz (19a) 4) 22 and 21 I get 27.235 MHz (22a/24)
It does not work for the other "A" channels, but it probably works for some of the skipped channels in the upper channels as well.
Night Ranger
|
|
Sandbagger
Administrator/The Boss
Posts: 6,245
|
Post by Sandbagger on May 28, 2015 20:54:36 GMT -5
Here comes some 1970s techno nostalgia.... If I balance the channel selector between... 1) 3 and 2 I get 26.995 MHz (3a) 2) 11 and 12 I get 27.095 MHz (11a) 3) 19 and 18 I get 27.195 MHz (19a) 4) 22 and 21 I get 27.235 MHz (22a/24) It does not work for the other "A" channels, but it probably works for some of the skipped channels in the upper channels as well. Night Ranger Oh yes, that was a big deal back during the first generation 23 channel PLL rigs. Many of our locals discovered those extra channels that way. At first I didn't believe them, since it wouldn't work with crystal rigs, and I didn't yet understand the difference. But once again, this prompted the FCC to step in and mandate that the manufacturers design defeat mechanisms which locked out the transmitter when the dial was moved off channel, when the next generation of radios came out (40 channel).
|
|
Sandbagger
Administrator/The Boss
Posts: 6,245
|
Post by Sandbagger on May 28, 2015 20:56:55 GMT -5
Adjusting the coil SHOULD fix it, as that is what you are compensating for. The VCO has a voltage range between about .5V to about 5V give or take. The voltage is dependent on the frequency of the oscillator, which is set by the LC values of the varactor diode and the tank coil. Move the coil value, and the VCO voltage moves the capacitance of the varactor to maintain frequency. Likewise, if you are hitting the edges of the VCO voltage ranges (either high or low), you can move the coil value to shift the VCO back into the usable range. Try it. Put your volt meter on the VCO voltage on one of your higher channels, and then adjust the coil and the voltage should swing up or down depending on which way you turn it. You should probably be turning it counterclockwise to decrease the inductance, which should shift frequency higher. If you can no longer compensate the frequency, then you've probably ran out of adjustment. I've never had that problem with the later 02a boards, but I can't comment on the 01's I went back and played with the VCO coil again (T-101). I was able to get it up to 27.655 MHz on channel selector 23 with programming pins 10 and 11 forced high. That matches the BCD code; 27.655 MHz - 24.965 MHz = VCO 2.690 MHz VCO 2. 6 9 MHz BCD 1 110 1001 I lost VCO lock on channel 1 at first, but I may have found the setting that allows the whole range. It is definitely at it's maxed VCO range as is. If channel 1 loses lock due to temperature changes I will sacrifice the higher channel to get stability on channel 1. If I can extend the VCO range that still leaves forcing programming pin 12 high for a BCD code of 1 111 1001 which should be VCO down mix frequency 2.790 MHz. 24.965 MHz + 2.790 MHz = 27.755 MHz. "1 000 0000" (CB channel 1) may be as low as it can go without reverting to straight binary mode. Night Ranger What happens when you enter 0 111 1001? I would think that should be 26.955.
|
|
|
Post by Night Ranger on May 28, 2015 22:21:14 GMT -5
I went back and played with the VCO coil again (T-101). I was able to get it up to 27.655 MHz on channel selector 23 with programming pins 10 and 11 forced high. That matches the BCD code; 27.655 MHz - 24.965 MHz = VCO 2.690 MHz VCO 2. 6 9 MHz BCD 1 110 1001 I lost VCO lock on channel 1 at first, but I may have found the setting that allows the whole range. It is definitely at it's maxed VCO range as is. If channel 1 loses lock due to temperature changes I will sacrifice the higher channel to get stability on channel 1. If I can extend the VCO range that still leaves forcing programming pin 12 high for a BCD code of 1 111 1001 which should be VCO down mix frequency 2.790 MHz. 24.965 MHz + 2.790 MHz = 27.755 MHz. "1 000 0000" (CB channel 1) may be as low as it can go without reverting to straight binary mode. Night Ranger What happens when you enter 0 111 1001? I would think that should be 26.955. So did I, but it appears (semi-guessing) pin 9 needs to be held high (5+ volts) with pin 8 at ground for the BCD mode to work. When I removed the voltage on pin 9 the VCO became unlocked at the bottom of it's range. This is my guess. If it went back to straight binary programming mode pins 8 through 15 would become the programming pins instead of pins 9 through 16 and pin 16 would become Vss (GND). To get to 26.955 MHz the down mixed VCO frequency would need to be at 1.990 MHz. That means an NCODE of 199. Since pin 8 is the highest power in binary mode it would have to be set high (128), and it is hard wired to ground. So...in binary mode pins 8 through 15 (P7 through P0) would be 00 11 11 00 (ignoring pin 16 at high) which is 0 + 0 + 32 + 16 + 8 + 4 + 0 + 0 or NCODE 60 in decimal. That would attempt to drive the VCO to 600 kHz since 600 kHz / 60 = 10 kHz. In binary mode it expects pin 16 to be Vss (GND), so I don't know how it would deal with it being +5 volts. If my theory is correct the only way to get this radio to go below channel 1 is to abandon BCD mode and program it in straight binary mode with an NCODE of 199 or less, OR switch out the down mix loop crystal with a lower frequency crystal. Night Ranger
|
|
Sandbagger
Administrator/The Boss
Posts: 6,245
|
Post by Sandbagger on May 29, 2015 7:55:59 GMT -5
What happens when you enter 0 111 1001? I would think that should be 26.955. So did I, but it appears (semi-guessing) pin 9 needs to be held high (5+ volts) with pin 8 at ground for the BCD mode to work. When I removed the voltage on pin 9 the VCO became unlocked at the bottom of it's range. This is my guess. If it went back to straight binary programming mode pins 8 through 15 would become the programming pins instead of pins 9 through 16 and pin 16 would become Vss (GND). To get to 26.955 MHz the down mixed VCO frequency would need to be at 1.990 MHz. That means an NCODE of 199. Since pin 8 is the highest power in binary mode it would have to be set high (128), and it is hard wired to ground. So...in binary mode pins 8 through 15 (P7 through P0) would be 00 11 11 00 (ignoring pin 16 at high) which is 0 + 0 + 32 + 16 + 8 + 4 + 0 + 0 or NCODE 60 in decimal. That would attempt to drive the VCO to 600 kHz since 600 kHz / 60 = 10 kHz. In binary mode it expects pin 16 to be Vss (GND), so I don't know how it would deal with it being +5 volts. If my theory is correct the only way to get this radio to go below channel 1 is to abandon BCD mode and program it in straight binary mode with an NCODE of 199 or less, OR switch out the down mix loop crystal with a lower frequency crystal. Night Ranger This is all just so confusing, as it's contrary to all the info that I have on this PLL chip. Nowhere does it talk about two different programming modes, and the data calls for straight binary programming. So this quasi-BCD mode stuff (and pin 16 not being ground) makes no sense, so all bets are off, as far as trying to predict reliably, where the limits of this chip's capabilities are. But on the other hand, it's kind of fun exploring in the dark. You never know what you might find....
|
|
|
Post by Night Ranger on May 29, 2015 11:32:35 GMT -5
So did I, but it appears (semi-guessing) pin 9 needs to be held high (5+ volts) with pin 8 at ground for the BCD mode to work. When I removed the voltage on pin 9 the VCO became unlocked at the bottom of it's range. This is my guess. If it went back to straight binary programming mode pins 8 through 15 would become the programming pins instead of pins 9 through 16 and pin 16 would become Vss (GND). To get to 26.955 MHz the down mixed VCO frequency would need to be at 1.990 MHz. That means an NCODE of 199. Since pin 8 is the highest power in binary mode it would have to be set high (128), and it is hard wired to ground. So...in binary mode pins 8 through 15 (P7 through P0) would be 00 11 11 00 (ignoring pin 16 at high) which is 0 + 0 + 32 + 16 + 8 + 4 + 0 + 0 or NCODE 60 in decimal. That would attempt to drive the VCO to 600 kHz since 600 kHz / 60 = 10 kHz. In binary mode it expects pin 16 to be Vss (GND), so I don't know how it would deal with it being +5 volts. If my theory is correct the only way to get this radio to go below channel 1 is to abandon BCD mode and program it in straight binary mode with an NCODE of 199 or less, OR switch out the down mix loop crystal with a lower frequency crystal. Night Ranger This is all just so confusing, as it's contrary to all the info that I have on this PLL chip. Nowhere does it talk about two different programming modes, and the data calls for straight binary programming. So this quasi-BCD mode stuff (and pin 16 not being ground) makes no sense, so all bets are off, as far as trying to predict reliably, where the limits of this chip's capabilities are. But on the other hand, it's kind of fun exploring in the dark. You never know what you might find.... I have a suspicion as to how this weird programming came about. Maybe the engineers at Cybernet were new to PLL and the PLL01a, so they poked and prodded with the pll01a until they found a way to make it work. Later someone told them they were doing it wrong and the later versions became straight binary. Just a guess though. I'll see if I can scan or take a picture of the two different wiring schemes for the PLL01a shown in the two different Sam's photofacts. The binary version is the later Sams Photofact, so it may be the later Cybernet version before the PLL02a replaced it. If you search the Ebay CB section for "Kraco" or "KCB" there are several KCB-2310,KCB-2320,and KCB-2330 models with no trailing letter. That is the crystal synthesis version. There are also several KCB-2310b,KCB-2320b, and KCB-2330b versions. Those are the PLL02a versions, but I did not see any "KCB-23xxa" versions. Perhaps the "a" versions were a short production run, and they were considered the "buggy" version. Night Ranger
|
|
|
Post by Night Ranger on May 29, 2015 14:25:04 GMT -5
Here is a photo of the Sams Photofact CB-106 for the Kraco KCB-2310a. Since it is a 3 page fold out it would not fit on my scanner. Note pin 8 is grounded and pin 16 is the lowest power programming pin on the pll01a. Kraco KCB-2310a PLL01a www.shadowstorm.com/images/KCB-2310a-PLL01a.jpgHere is a photo of the Sams Photofact CB-137 for the HyGain 681/682 pll01a. Notice pin 16 is grounded, pin 15 is the lowest power programming pin, and pin 8 has 5.36 volts on it. Also note there is a typo on the first page that says "PLL02a FREQ DET." and the second page says "PLL01a". The semiconductor parts list at the end of the HyGain section says PLL01a. www.shadowstorm.com/images/HyGain-681-682-PLL01a.jpgNight Ranger
|
|
|
Post by Night Ranger on May 31, 2015 20:43:54 GMT -5
Adjusting the coil SHOULD fix it, as that is what you are compensating for. The VCO has a voltage range between about .5V to about 5V give or take. The voltage is dependent on the frequency of the oscillator, which is set by the LC values of the varactor diode and the tank coil. Move the coil value, and the VCO voltage moves the capacitance of the varactor to maintain frequency. Likewise, if you are hitting the edges of the VCO voltage ranges (either high or low), you can move the coil value to shift the VCO back into the usable range. Try it. Put your volt meter on the VCO voltage on one of your higher channels, and then adjust the coil and the voltage should swing up or down depending on which way you turn it. You should probably be turning it counterclockwise to decrease the inductance, which should shift frequency higher. If you can no longer compensate the frequency, then you've probably ran out of adjustment. I've never had that problem with the later 02a boards, but I can't comment on the 01's I went back and played with the VCO coil again (T-101). I was able to get it up to 27.655 MHz on channel selector 23 with programming pins 10 and 11 forced high. That matches the BCD code; 27.655 MHz - 24.965 MHz = VCO 2.690 MHz VCO 2. 6 9 MHz BCD 1 110 1001 I lost VCO lock on channel 1 at first, but I may have found the setting that allows the whole range. It is definitely at it's maxed VCO range as is. If channel 1 loses lock due to temperature changes I will sacrifice the higher channel to get stability on channel 1. If I can extend the VCO range that still leaves forcing programming pin 12 high for a BCD code of 1 111 1001 which should be VCO down mix frequency 2.790 MHz. 24.965 MHz + 2.790 MHz = 27.755 MHz. "1 000 0000" (CB channel 1) may be as low as it can go without reverting to straight binary mode. Night Ranger I forced pins 10,11,and 12 high. Channel 17 became 27.665 MHz, but on higher channels the VCO became unlocked again. Time to change the varactor diode and parrallel two varactor diodes as you (Sandbagger) suggested or try a different varactor diode. The stock varactor diode is an ITT410. I have a few brand new Sanyo SVC251SPA varactor diodes here. I may be able to use those in this chassis. Here is the datasheet for the SVC251SPA varactor diodes. pdf.datasheetcatalog.com/datasheet/sanyo/ds_pdf_e/SVC251SPA.pdfThere is also a dealer on Ebay selling NOS ITT410 varactor diodes for a very reasonable price. Night Ranger
|
|
|
Post by Night Ranger on Jun 24, 2015 9:20:22 GMT -5
I added the "A" channels and skipped channels above 23 that end in X4 and X9. I used a single pole double throw center off switch. All the way to the right is normal, center off interrupts the channel selector and forces no voltage to pin 16, and all the way to the left forces pin 16 high. I may add a small piece of angled metal on the bottom of the radio to add missing features such as RF Gain, modulation adjust, modulation boost, AWI (antenna SWR warning indicator) etc. I'm also considering adding a direct audio line in to either the TA7205p audio chip and maybe even direct audio to the driver and final input for high fidelity transmit audio. I might also add a line level output for audio recording. This little Kraco may look like a Borg drone by the time I get finished "assimilating" it. Night Ranger
|
|
|
Post by cbrown on Jun 25, 2015 8:26:52 GMT -5
Should be a pretty nice radio once you get all the mods done.
|
|
|
Post by Night Ranger on Jun 25, 2015 8:29:14 GMT -5
Should be a pretty nice radio once you get all the mods done. Yep, but unless I mount it in a new base chassis it is probably going to be butt ugly to look at. Night Ranger
|
|
|
Post by cbrown on Jun 26, 2015 8:25:58 GMT -5
Sounds like a job for a nice custom cabinet!
|
|
|
Post by Night Ranger on Jun 26, 2015 8:34:21 GMT -5
Sounds like a job for a nice custom cabinet! I thought about mounting it inside another radio chassis. For awhile I used a Regency CR-230 mobile as a base when I was a teenager. I kind of liked the S/RF/SWR meter, and it would have a nostalgic look for me. If I were to use a base chassis a Pearce Simpson Bearcat 23c looks great, and there is plenty of room in the chassis. Neither of those radios have very good selectivity due to the first IF frequency not being fixed (14 crystal synthesis scheme), so the Krazy Kraco with two fixed IF frequencies and my added dual 455 kHz ceramic filters would receive less bleedover. Regency CR-230 www.shadowstorm.com/cb/rigs/Regency-CR-230-new-3.jpgPearce Simpson Bearcat 23c radiopics.com/CB_Radio/USA%20CB/3-Base/Pearce-Simpson/Photos/Pearce-Simpson_Bearcat%2023C.jpgNight Ranger
|
|
Sandbagger
Administrator/The Boss
Posts: 6,245
|
Post by Sandbagger on Jun 27, 2015 19:07:39 GMT -5
Sounds like a job for a nice custom cabinet! I thought about mounting it inside another radio chassis. For awhile I used a Regency CR-230 mobile as a base when I was a teenager. I kind of liked the S/RF/SWR meter, and it would have a nostalgic look for me. If I were to use a base chassis a Pearce Simpson Bearcat 23c looks great, and there is plenty of room in the chassis. Neither of those radios have very good selectivity due to the first IF frequency not being fixed (14 crystal synthesis scheme), so the Krazy Kraco with two fixed IF frequencies and my added dual 455 kHz ceramic filters would receive less bleedover. Regency CR-230 www.shadowstorm.com/cb/rigs/Regency-CR-230-new-3.jpgPearce Simpson Bearcat 23c radiopics.com/CB_Radio/USA%20CB/3-Base/Pearce-Simpson/Photos/Pearce-Simpson_Bearcat%2023C.jpgNight Ranger I like the base station cabinet idea, as it provides much more room to cram in goodies to make that "Frankenradio" work the way you want, and still look reasonably stock. One of these years I want to finish my project. I have a Uniden PC-66 mobile rig that was missing covers and the faceplate was pretty well banged up. I stripped out a non-working SBE Trinidad and I plan on putting the Uniden radio in there, along with a single transistor amp. The radio, of course, would be HiFi audio modified, along with a few other additions. But that project is way on the back burner.....
|
|
|
Post by Night Ranger on Jul 6, 2015 8:24:42 GMT -5
|
|
Sandbagger
Administrator/The Boss
Posts: 6,245
|
Post by Sandbagger on Jul 6, 2015 9:22:49 GMT -5
Interesting...... I was not aware that Cybernet continued the 01a PLL into any 40 channel design. There were a number of factory refurbs that took the remaining 23 channel radios in the pipeline and refitted them with 40 channel switches, once 1977 rolled around. Maybe these schematics were for those radios.
|
|
|
Post by Night Ranger on Jul 6, 2015 9:42:14 GMT -5
Interesting...... I was not aware that Cybernet continued the 01a PLL into any 40 channel design. There were a number of factory refurbs that took the remaining 23 channel radios in the pipeline and refitted them with 40 channel switches, once 1977 rolled around. Maybe these schematics were for those radios. Possibly. There is one such Hy-Gain radio on Ebay at the moment. There is a sticker on the back of the radio that says; "This equipment is modified under a waiver granted by the FCC on November 10, 1976". Night Ranger
|
|
Sandbagger
Administrator/The Boss
Posts: 6,245
|
Post by Sandbagger on Jul 6, 2015 10:42:22 GMT -5
Interesting...... I was not aware that Cybernet continued the 01a PLL into any 40 channel design. There were a number of factory refurbs that took the remaining 23 channel radios in the pipeline and refitted them with 40 channel switches, once 1977 rolled around. Maybe these schematics were for those radios. Possibly. There is one such Hy-Gain radio on Ebay at the moment. There is a sticker on the back of the radio that says; "This equipment is modified under a waiver granted by the FCC on November 10, 1976". Night Ranger Hy-Gain must have bought a lot of 23 channel PLL radio stock prior to the end of 1976, as the Hy-Gain models are the ones I saw that were factory refurbed for 40 channel operation, and they were the ones selling off obsolete boards (that were used to build 10 meter and 6 meter ham projects) for dirt cheap a while later.
|
|