Wednesday, December 3, 2014

Marantz Model 22 Receiver

Marantz Model 22

Heres a  fun one, a Marantz Model 22, back when Marantz started going over seas to Japan, we see some of the  techniques used here on the 22XXs a lil later on.

P800 Power Supply
The 1000uf capacitors have a common ground/case not typically in later variants, the trick is getting the right lead spacing here. The particular power supply is rather interesting, consisting of a dual power supply, on half is dedicated to the AM/FM stages and the rest for amplifier phone/pre sections. P600 and P700 PCB's.
Lytics here were replaced with Panasonic FR and FC's. 

A new EG1018-ND switch with a vishay X1Y2 safety capacitor was installed.  The large can caps were replaced with my favorite low profile 4700uf Panasonic THA's. 

P400 Tone
Silmics and Nichicons were used extensively on this board, transistors at H401/402 were replaced with matched hfe KSC1845's. 

P300 Phono
This is a pretty familiar design I've, the lyrics here were replaced with Silmics and Nichicons

P600/700 DC FM/AM Amplifier
The latter half at P600 is used for the amplifier board on this model through the dual PS. Just a few lyrics here to replace with Nichicons, I also replaced the large films with Panasonic ECW PP type. The Bias can be obtained across either emitter resistors R651-654, adjustments are bad off the board back behind the transistor TO-3 bank, the pots center stage are Offset adjustments. New Mica insulators and thermal compound was applied.  P700 was recapped with Nichicons and Silmics along with H705/706 (2SC732) replaced with  matched KSC1845's.

I also recapped the speaker relay PCB at P980 with Nichicons while we have access and are addressing the PS and such.

Heres a listed of noted service bulletins -C807
-R617/618 9.1K 1/2 RESISTOR (WAS 10K) 
470uf to 330uf @ c804
H801/802 Transistor Upgrade (done prior on most units)

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