I got a Sherwood S-9910 to service and recap, this thing is a big receiver! No known problems, except that the controls need Deoxit applied to them, which I'll be doing. I'll be replacing all the caps, including the filter caps, along with all the transistors in the preamp sections. I'll also be pulling the outputs and re-greasing them along with cleaning the relays. The caps I'll be using are Nichicon PW for the power amp and power supply sections, Panasonic FC for the preamp sections, Nichicon KL for the blue and orange low noise caps and Panasonic ECQ film caps for any caps under 1uF. Here are a few specs on this receiver:
100 watts per channel into 8 ohms
4 gang tuner with a 1.7uV sensitivity
Triple tone controls and adjustable input sensitivity for the phono 2 input
Weighs 41 lbs
Here are some before pics of the boards and other stuff:
Tuner board
Phono preamp board
Tone control board
Tape/Mode board
Driver boards
Power transistor/relay board
Power supply board
Filter caps
Tuning capacitor
And here is after!
Tuner board
Phono amp board
Tape/Mode board
Tone amp board
Driver and power transistor/relay boards
Power supply board
New main filter caps
Great job. I have one of these I would like to recap and know that you have done two of them. Which one sounded better. Do you have a parts list of the caps used in that receiver that you could post or email me. Regards, Jerry
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ReplyDeleteHi Matt,
ReplyDeleteDefiantly bitten by the Solid State Bug and enjoy seeing the fine work you do on these receivers. I have a couple more questions on the Sherwood.
1) is there a way to set the offset and Bias using a volt meter. The service manual shows methods using a distortion meter and variac with a watt meter? If so, what would you recommend?
2) when you did your mods, what value did you use for the large filter caps and what brand?
Thanks again for helping me with my mod. It is a real blessing to me. Regards, Jerry
For the bias, connect your meter leads between pins 7 & 8 for the left channel and pins 9 & 10 for the right and adjust the bias pots for about 30mV. The offset is not adjustable on this amp.
DeleteI used these filter caps here: http://www.digikey.com/product-detail/en/E36D750MLN183TC79M/565-3331-ND/2095945?cur=USD
Hi Matt,
DeleteWell, I have removed thePwer Amp driver boards and have received some parts ready to upgrade. I noticed in the photo, you did not have C611 (120P) cap installed in your mod. I was going to bypass with a 120P Polystyrene. Is there any reason why you did not have it installed to bypass the transistor? Also, I was thinking of replacing all transistors and diodes. Do you happen to have a list of parts you would recommend for these devices? Thanks.
I did not bypass it because it already had the 120p bypass cap soldered in underneath the board. And no, I do not have a list of parts to replace those devices.
DeleteThanks,
ReplyDeleteJerry