• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Magnavox AMP185-11 bad transformer

D

dstiltner

New Member
I'm currently restoring a Magnavox 1sp209f with a AMP185-11. The power transformer is not working. I've tested the output leads however its reading 0 volts. The primary winding is reading O.L (no continuity) and one of the secondary winding is showing O.L (no continuity).

The transformer is stamped "Magnavox D300085G1".

Does anyone have a recommendation for a replacement transformer for this unit? Keep in mind I'm looking to keep the original circuit.
 
Register to hide this ad
Welcome! :music:

Although I do not doubt that the transformer is bad, but those things are kinda hard to kill.

Was there a puddle of tar underneath the chassis where the power transformer was located?

I am hoping that maybe you will know that you will need to jump 2 pins on the power molex socket to get the power to come on.

You can also connect a lampcord type plug directly to the two black wires that come out of the power transformer. This will be a direct power on until you put a switch across the line.

If you have the original turntable and umbilical, you can just use that temporarily to power up the amp until you can rewire or jump the molex socket.

Let us know! We're here to help. :thmbsp:
 
No puddle of tar, so that's good. I didn't think about using the switch on the turn table as I'm refinishing the cabinets. I'll jumper the molex, do you know which pins?
 
Ok, I hooked it up in the garage and everything looks good. Going to need to replace the caps. However, I brought it back in the house and tried it again and the rectifier tube started flashing/sparking. I do not have a tube tester so I'm going to just order all new tubes.
 
dstiltner said:
Ok, I hooked it up in the garage and everything looks good. Going to need to replace the caps. However, I brought it back in the house and tried it again and the rectifier tube started flashing/sparking. I do not have a tube tester so I'm going to just order all new tubes.
Click to expand...

Good to hear the PT is good after all.
Replace those electrolytics and coupling caps. You may find some of those carbon comp resistors have drifted out of spec too.

Regards, Bob
 
After inspecting the rectifier, I've located a broken filament.

Thanks for the suggestions and help. I will post pictures after I'm finished with this project.
 
usually the rectifier tube will fail from bad filter caps. Once they arc, they're basically done for. Replace the caps and the rectifier and it should be functional.
 
You must log in or register to reply here.
Back
Top Bottom