Radio Make and Model: MAJOR 788
PCB Number: PTBM133A4X
PLL Number: PLL02
Test gear available: TEST METER
Symptoms: no tx or rx
What is working: it lights up
What has been tried: nothing as yet dont want to break it even more
Did it suddenly happen ?: no was brought like this
Anything else that may be of help?:
Hi guys i brought this because ive been after one for years now to add to my collection of majors, it lights up changes channels etc it has no tx has ive tried it sat next to another radio and vice versa any help would be greatful
Right thought i would have a bash got nothing to loose,so i had a play with the vco i did get some locals to me and the radio did tx but only halfway on the signal meter and also if i changed channel they would be on the next one too , then its gone again wont key up,ive checked voltage on pll02 pin 1 and i get 5.6v
MAJOR 788 NO TX OR RX
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- Newbie
- Posts: 8
- Joined: Friday 1st Jan 2010, 2:59
- First Name: shaun
- Location: uk
MAJOR 788 NO TX OR RX
Last edited by ranger6900f on Wednesday 15th Dec 2010, 12:04, edited 1 time in total.
Re: MAJOR 788 NO TX OR RX
Check the AVR transistor Q34, it's a darlington transistor 2SD837 or replace it with a new one to be on the safe side, also check the zener diode at it's base pin at the other side of L17.
I don't know the radio but that's what I'd start with as it's the voltage regulator.
I don't know the radio but that's what I'd start with as it's the voltage regulator.
How far is it.
Twice it's length from halfway.
Twice it's length from halfway.
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- Newbie
- Posts: 8
- Joined: Friday 1st Jan 2010, 2:59
- First Name: shaun
- Location: uk
Re: MAJOR 788 NO TX OR RX
hi zodiac (dave????) i have read somewhere else about the darlington q34 so i will try this next, i think the board is the same a mm3 and the concorde 3 if this helps
Re: MAJOR 788 NO TX OR RX
Yes it is the same board but I've been lucky and never had to work on one yet. 

How far is it.
Twice it's length from halfway.
Twice it's length from halfway.
-
- Newbie
- Posts: 8
- Joined: Friday 1st Jan 2010, 2:59
- First Name: shaun
- Location: uk
Re: MAJOR 788 NO TX OR RX
hi guys just to let you know it was the vco that was at fault,good mate of mine has done but thanks dave for your help

