I’m in need of help regarding service work I’m trying to perform on (3) 148GTL’s. All three are the older models with the 8 pin IC4, side access mic 8 pin mic plug, and MB8877 chip. I think you get the idea. All 3 have been modified and hacked-up pretty good.
Anyway, I ordered the Sams pub for it and was pleasantly surprised they are still in business however, I’m discovering maddening discrepancies. First, I can’t read the schematics as my eyes are almost done. Secondly, my radios all have a VR7 which doesn’t appear anywhere on the schematics or BOM (bill of materials). Sams also neglected to include a list of resistors and values. Etc.
Here’s my itch. In trying to determine why there’s no am modulation. I found no 6.83v available from a #3 branch originating from a 8.14v leg from IC4. It does read just over 3v now in receive AM mode. One schematic shows exactly what I’m describing but then another schematic shows a different configuration at IC4…plus I can’t read but so much then I have to stop. Fuzzy print, misleading schematics and faulty eyes makes an old man whine.
Question: Is there a clean and readable schematic w/voltages available in large 11x17 format for this older version?? By the way, it wouldn’t do much of anything when I first popped it open. It’s slowly returning to life but that damn 6.83v leg has me stumped. I can get it if I had the proper docs.
Thanks es 73
Anyway, I ordered the Sams pub for it and was pleasantly surprised they are still in business however, I’m discovering maddening discrepancies. First, I can’t read the schematics as my eyes are almost done. Secondly, my radios all have a VR7 which doesn’t appear anywhere on the schematics or BOM (bill of materials). Sams also neglected to include a list of resistors and values. Etc.
Here’s my itch. In trying to determine why there’s no am modulation. I found no 6.83v available from a #3 branch originating from a 8.14v leg from IC4. It does read just over 3v now in receive AM mode. One schematic shows exactly what I’m describing but then another schematic shows a different configuration at IC4…plus I can’t read but so much then I have to stop. Fuzzy print, misleading schematics and faulty eyes makes an old man whine.
Question: Is there a clean and readable schematic w/voltages available in large 11x17 format for this older version?? By the way, it wouldn’t do much of anything when I first popped it open. It’s slowly returning to life but that damn 6.83v leg has me stumped. I can get it if I had the proper docs.
Thanks es 73