Help to identify

[cademan]

I guess my simple question to you is do both units work even though one has a buzz and one has no diodes?

 

[by the way]

I guess my simple question to you is do both units work even though one has a buzz and one has no diodes?

Without the diodes.

 

[by the way]

Without the diodes.

Without the diodes in the main amp. A lot of parts were removed when the external part was put in.

 

[cademan]

Without the diodes in the main amp. A lot of parts were removed when the external part was put in.

Okay I get that but does it still work right now as is? I'm trying to figure out that if it is currently working without the diodes and some parts removed? I have been doing this 40+ years and I know about modifications. It looks like a shop or professional or both did the modifications.

If this is the one with the slight hum, then you need to be looking at the power supply and not the missing diodes or parts.

 

[cpt_paranoia]

It looks like a shop or professional or both did the modifications.

Hard to tell what has been done, but I see what look like TO-3 sockets on those heatsinks, so did they replace the germanium output devices with something with more poke, on a heatsink? If so, did they move the diodes to those output devices?

 

[by the way]

Okay I get that but does it still work right now as is? I'm trying to figure out that if it is currently working without the diodes and some parts removed? I have been doing this 40+ years and I know about modifications. It looks like a shop or professional or both did the modifications.

If this is the one with the slight hum, then you need to be looking at the power supply and not the missing diodes or parts.

I will look at the power supply closer. Will power supply cause the buzz as well as the hum?
Yes it does work and sounds good. The noise is noticeable both when something is plugged into the amp and also with nothing plugged in.

 

[by the way]

I will look at the power supply closer. Will power supply cause the buzz as well as the hum?
Yes it does work and sounds good. The noise is noticeable both when something is plugged into the amp and also with nothing plugged in.

The only reason I was looking for the diodes was in case I wanted to take the amp back to original…prior to modifications were made. At least that way I would have a matching schematic to work with.

 

[by the way]

Hard to tell what has been done, but I see what look like TO-3 sockets on those heatsinks, so did they replace the germanium output devices with something with more poke, on a heatsink? If so, did they move the diodes to those output devices?

They did not move the diodes.

 

[petehall347]

those motorola i believe are silicon .
i found this interesting cross referencing pdf .
https://flippers.com/pdfs/Seeburg_Hab_Cross_Reference.pdf

 

[cademan]

I will look at the power supply closer. Will power supply cause the buzz as well as the hum?
Yes it does work and sounds good. The noise is noticeable both when something is plugged into the amp and also with nothing plugged in.

Usually it is bad power supply capacitors that cause hum in both channels but it looks like I see a couple of new capacitors there?
If a diode or bridge rectifier is leaky, it can pass AC and cause hum. You can replace the diode with a 1N4007 / UF4007 diode or make a bridge with either / or.

If it were me, I would just get 'em both working and leave the modified one alone except for finding the hum problem. The one with the diodes is most likely the original.

Trying to convert one to the other or vice versa just seems like a pain.

 

[by the way]

Usually it is bad power supply capacitors that cause hum in both channels but it looks like I see a couple of new capacitors there?
If a diode or bridge rectifier is leaky, it can pass AC and cause hum. You can replace the diode with a 1N4007 / UF4007 diode or make a bridge with either / or.

If it were me, I would just get 'em both working and leave the modified one alone except for finding the hum problem. The one with the diodes is most likely the original.

Trying to convert one to the other or vice versa just seems like a pain.

The un modified amp works perfectly and is currently installed in a jukebox and is performing very well. No plans on working on that one. I was only comparing. I did install all new capacitors in the problem amp which didn’t change the noise issue.
I will study the power supply and see what happens from there.

 

[cademan]

Is that the Seeburg HSC1 home stereo jukebox?

I have always liked Seeburg home stuff.

 

[by the way]

Is that the Seeburg HSC1 home stereo jukebox?

I have always liked Seeburg home stuff.

Yes it is. Awesome unit for sure!