2/10/2014

Silvertone 7407 Refurbish

Picked up this Silvertone from an Antique store for $20 not working. The receiver chassis number is 528.54746 and the Amplifier is 528.69240 There is a number stamped on the amp chassis 30-125-2 or it might be 30-125-2a.
 It was plugged in and probably in use at one time at the antique store.

All it is, is a Silvertone Console Tuner, and amp Chassis inside a table top cabinet.
It appears to be all original inside.

It was in need of a recap.

This is the Schematic of my amp as found.

It has dual station dials, and indicator lights for being on station (in Mono),
 And in Stereo.

I had to replace:
1 - 6be6
1 - em84 with a NOS one from ebay.
2 - 6bq5
The resistor on the em84 eyetube.
all the electrolytics
several resistors on the right channel of the amp (the left all measured good).
There was 1 burned and split resistor in the tuner, and one singed resistor in the power supply.
I blew up a 100uf e-cap in the voltage doubler and had to replace that with a much higher voltage rated one. Seems that the amp originally had a 200vdc cap in the voltage doubler circuit. Why mine blew I do not know. The replacement 450vdc cap works fine. It has a Phono and Tape in. I have a CD player or mp3 player on the Tape In.
For $20+$45 in parts to fix, you can't get much better than that. It sounds really good through my Fisher XP-9C Speakers.

5 comments:

dgb said...

Hi, I may have a chance to acquire one of these and I was wondering how you connected your cd player to the odd tape connector.

Flinx said...

I removed the tape connector and fabricated a new board with a 3.5mm stereo jack, then used a headphone connector to RCA adapter.

Flinx said...

here is pic https://imgur.com/ST5XG7M

Anonymous said...

Do you have a larger pic of the schematic for this? I have the amp out of one and would like to see what the voltages from the transformer are in case I want to make a guitar amp out of it. Thanks

Flinx said...

the schematic is here: https://www.dropbox.com/s/nf0lhr1gi0kdzqf/SAMS%20silvertone%207407.pdf?dl=0

When it asks you to login or create an account click "no Thanks, Continue to View"
Then Click Download in the upper right corner.