Blackface pres Jackson no receive

[junon600]

I have a nice Black Jackson. Trans is good all around on SSB, AM, and FM. FM receive seems to be there. However I have no receive on AM, and SSB. Not a mic wiring issue, and if I trans a strong signal near the radio it will barely come through. So I would think this has to be in the rec amp section. Anyone ever heard of this before. I got this radio for next to nothing, and have always wanted one. If I could get it running it would be great. Like I said the trans side is perfect and spot on, just no AM, and SSB receive.

 

[Dr_DX]

Are you getting voltage out of the RX only voltage regulator?

 

[junon600]

To be honest, I'm not sure. I will have to look it up i the schem and find out. I haven't done too much digging yet. I wanted to see if it was a common issue with a common solution first.

 

[junon600]

Looked at the schematic, and am none the wiser. This one may just end up dead shelf fodder.

 

[jazzsinger]

After filter 4 on the schematic fm veers of to TR8 as its dual conversion,AM/SSB is single conversion and continues through filter 5 TR14,filter6,TR15,TR16 and TR17.

After TR17 AM and SSB take seperate paths,so the logical conclusion would be something in that strip between filter 4 and TR17 is either short circuit to ground or open circuit on the signal path.Probing each stage input and output with an rf probe or scope should show up the guilty part.Alternatively you could take voltage measurements on TR14,TR15,TR16 and TR17 as these active components are most likely where the trouble lies.

Some food for thought for you.

Another possibility is someone has been dicking around with L9,so it may be worth trying to peak that to see if rx on AM/SSB returns,as its a common problem when people go in radio's messing about with transformers they know nothing about.

 

[junon600]

Thanks Jazz, I will look into it when I get home this eve. Will let you know how it goes. Much appreciated.

 

[jazzsinger]

Hope you get it going mate,although not the best AM transceivers due to low level AM modulation,I imagine the reason they ain't so popular in the states with the distorted loud audio crowd,they are absolutely superb on SSB and very good on FM.

A true SSB dream machine.They have an awesome reputation in Europe where SSB and FM are the main modes of transmission.Awesome tx audio,rivalling many far more expensive hf radio's and bettering many of them too even with just the standard dynamic microphone,put an Astatic teardrop 575-m6 on it and its priceless audio.