4
443
Guest
I have an older style 2950 and I recently had a problem with it warbling on SSB and checked the power cord and the power cord I was using was on only like 20 awg! I replaced that cord with the proper cord 16awg and now I don't have that problem. Running it on an Astron RS-12A 9 amp cont. 12 amp peak supply.
Anyhow, I now want to do some modifications to this thing and I came across a few and wanted feedback if anyone else has done these things to see if they got the claimed results before I got the parts and spend hours doing these.
For more stability and better modulation:
Change Q51 from 2SB754 to 2SB688 or even better 2SB817
For better sound quality
Change Q53 to 2SA473
To improve low power swing:
Change R178 to a 3k ohm.
Change R194 (10k ohm) with 4.7k.
Change R281 (4.7k ohm) with 10k.
For more output on AM and SSB:
Parallel C270 with a 470pF ceramic disc capacitor.
For better receive:
Change D34 and D35 from 1N60s to ECG583
For even more ouput:
change finals from 2SC2312 to MRF 477 or MRF 497
How much retuning is involved in these. Am I going to have to retune the output? Are any of these mods going to cause me to be off frequency without retuning? I don't have a scope or freq probe to retune it with.
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Anyhow, I now want to do some modifications to this thing and I came across a few and wanted feedback if anyone else has done these things to see if they got the claimed results before I got the parts and spend hours doing these.
For more stability and better modulation:
Change Q51 from 2SB754 to 2SB688 or even better 2SB817
For better sound quality
Change Q53 to 2SA473
To improve low power swing:
Change R178 to a 3k ohm.
Change R194 (10k ohm) with 4.7k.
Change R281 (4.7k ohm) with 10k.
For more output on AM and SSB:
Parallel C270 with a 470pF ceramic disc capacitor.
For better receive:
Change D34 and D35 from 1N60s to ECG583
For even more ouput:
change finals from 2SC2312 to MRF 477 or MRF 497
How much retuning is involved in these. Am I going to have to retune the output? Are any of these mods going to cause me to be off frequency without retuning? I don't have a scope or freq probe to retune it with.
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