president jackson alignment issue- PB042AE

[tozitom]

Hi techs!
I'm slowly comming back to my old passion, electronics repair! and few days ago I received this jackson CB Radio on my bench from a friend, to give a full restoration, also it was out of frequ as he said. After inspection/measurments it's really out of frequ so I've started a full alignment as per the manual; I've donne so far the carrier and receive parts, but I've a doubt on 1º step for "CARRIER OSCILLATOR PORTION". The manual states:
- CH: 40, Band: E, Mode: RX AM, Clarifier: Center
- DC Voltmeter to TP2
- Adjust L12 for 6 V +/- 0.1 V + Confirm 2 V on CH 1 Band A
The thing is if I ajust 6v on TP2 (Band E + Ch 40) I get 2,8V on CH 1 Band A
If ajusting 2V on TP2 (CH 1 Band A) I only get 4,87V on CH 40, Band E

that seems not to be critical as I can get the correct frequencies on all bands... but would like to know your opinion.
Thanks to all.

[CJay]

Which manual are you using and does it match the board you have?

Some of the manuals (notably the CB City ones) are terribly vague and sometimes completely wrong but then so are the original manuals so it's often a case of wokring out what you should actually be doing instead of what the manual says you should do.

Plus, lots of these radios have been modified to within an inch of their lives so you'll often need to work out what the radio is doing compared to what the manual thinks it should be doing.

Things to check, compare the PLL N-Codes the manual says you should have to the ones the PLL is 'seeing', check the band crystal is what you expect it to be as well, both of those will have an effect on the VCO control voltages

[tozitom]

thanks for reply.
I've been following those 2:
http://www.radiomods.co.nz/alignments/presidentjacksonalign.html
http://www.cbradio.nl/president/Service_Manual_President_Jackson_226ch_Old_Silver_version_Homer_ENG.pdf

[CJay]

OK, they're pretty much the same, grab a copy of the Export manual but first, check this sheet out

http://www.zen96216.zen.co.uk/cb/uniden-esm-06.htm

Your downmix input frequency is the N-Code, so Ch1 Band E should have an N-Code of 262 on the P0-P whatever pins of the MC145106, if it's not then the radio is modded.

Verify the Loop crystal fitted is the correct one too.