I had similar amplitude sine waves on all bands at the out pin of the low level driver board. Recently, it got worse, which proved to be a lucky break because it made me think. Although that helped improve things, I still had very strange results with 80 meters - as i advanced the drive with the band switch set to 3.5MHz I still saw some fluctuation on the power supply ammeter and it never got past 5 amps. I did some of the basic things such as cleaning the front panel potentiometers and removing and replacing the boards.
Things on the Triton IV analog have improved. I thought i would post a follow up on this in case it is a benefit to other people. Hi all - thanks to Allison, Lynn, Charles and Joe for your suggestions.
Allison - No direct email, it goes to bit bucket! I will not see it. I've seen a few Argos with similar regulator issues.
After that the RX was generally better and TX full power with normal adjustment behavior. I drew up the modified schematic and taped it to the inside should any other person work on it. The owner wanted it to work and I offered the option to sort it out as stock or apply a hard fix. The 7808 was the very common to220 package easily found. IF any one does the 7808 input is pins 11 and 12, ground is pin-7, and out is pin-3. Input to the 7808 is C6 sand the output is to +reg with an added 10uf from the +8 to ground under the board. After looking at it I replaced the 723 and resistors R24,25,26,27 C3 and C4 with one 7808 and that was a far. THe 723 can regulate to about 100ma but this one seemed to have issues at about 50ma even with new part. Replaced that but it was not a hard regulator. The 723 regulator was sorta working but really correctly and the 8V bus tended to sag to as low as 6V on TX. I just worked on a 340 for a local and it had a oddit with low power and it was on the regulator control board 80280. I shot them with de-oxit and rotated them a few time and shot them again. The drive pot is a dual unit ad pulling it apart is not easy or desireable. They all seem to be functioning correctly when I test them out Going to the Darlington pair Q2 and Q3 on the SWR-ALC board. On the SWR-ALC board, I haveĬhecked C1 and Q1, and then D6 which controls the base voltage Some fluctuations in the ammeter on the 252M before it finally 7Mhz often hangs out at 5MHz and 3.5Mhz causes Thing is, the ammeter never gets above 9Īmps on 28 MHz. I am supposed toĪdjust R-8 to keep the draw from the power supply (Model 252M)Īt or below 18 amps.
The manual (pģ-31) says the ALC panel control and R-8 on the SWR-ALC boardĬontrol the overall gain on the amplifier. Some help with a mystery I have encountered. I haveīeen going through all of the tests in the manual. They all seem toīe functioning correctly when I test them out of circuit.įor my brother and me but spent many years in storage while weĭid adult stuff. On the SWR-ALC board, I have checked C1 and Q1,Īnd then D6 which controls the base voltage going to theĭarlington pair Q2 and Q3 on the SWR-ALC board. In the ammeter on the 252M before it finally settles down atĪround 9 amps. Thing is, the ammeter never gets above 9 amps on 28 MHz.ħMhz often hangs out at 5MHz and 3.5Mhz causes some fluctuations Keep the draw from the power supply (Model 252M) at or below 18Īmps. The ALC panel control and R-8 on the SWR-ALC board control the Going through all of the tests in the manual. It was the childhood rigįor my brother and me but spent many years in storage while we didĪdult stuff. Any suggestions of a possible cause? Thanks very much and 73, Doug They all seem to be functioning correctly when I test them out of circuit. On the SWR-ALC board, I have checked C1 and Q1, and then D6 which controls the base voltage going to the Darlington pair Q2 and Q3 on the SWR-ALC board. 7Mhz often hangs out at 5MHz and 3.5Mhz causes some fluctuations in the ammeter on the 252M before it finally settles down at around 9 amps. Thing is, the ammeter never gets above 9 amps on 28 MHz. I am supposed to adjust R-8 to keep the draw from the power supply (Model 252M) at or below 18 amps. The manual (p 3-31) says the ALC panel control and R-8 on the SWR-ALC board control the overall gain on the amplifier.
I could use some help with a mystery I have encountered. I have been going through all of the tests in the manual. It was the childhood rig for my brother and me but spent many years in storage while we did adult stuff.