700II resistors/diodes

[SG700II]

Want to swap these out. Looks like they warmed up in the past.

From the schematic, seem to be R1 and R101. Not sure which are the diodes, and their value.

 

[J!m]

Those little things you circled look like diodes to me.
The big ceramics are resistors.

 

[SG700II]

Those little things you circled look like diodes to me.
The big ceramics are resistors.

Correct, im trying to figure out which diodes these are on the schematic, to inturn know their type.

 

[laatsch55]

D1 is a 1N4744, D101 is a 1N4148

 

[laatsch55]

If you demount them they will be marked..

 

[SG700II]

If you demount them they will be marked..

D1 is a 1N4744, D101 is a 1N4148

Perfect, thank you for the info and tip.

 

[laatsch55]

You are welcome...

 

[MarkWComer]

I thought it strange that they never drilled holes for the wire connections at the bottom of the boards.
Seems a bit tenuous to me, an opportunity for failure.

 

[J!m]

Gotta keep those repair techs employed.

 

[Hexis22]

The components you're looking for are R1, R2 (2.4K, 5W) and D1, D2 (Both 1N4744) as shown in following schematics and diagram from service manual:

 

[SG700II]

The components you're looking for are R1, R2 (2.4K, 5W) and D1, D2 (Both 1N4744) as shown in following schematics and diagram from service manual:

Thank you very much. This clears up my confusion.

 

[Sunnbobb]

Same parts I found "browned" on the PL36 board I just replaced with a WOPL board. I replaced the parts, but they still heated up to an unacceptable level. Keep track of the orientation of the Diodes. I seem to remember having a question about that with the PL schematic vs what I found installed. May have been a mistake of a previous tech, not sure.

 

[SG700II]

Same parts I found "browned" on the PL36 board I just replaced with a WOPL board. I replaced the parts, but they still heated up to an unacceptable level. Keep track of the orientation of the Diodes. I seem to remember having a question about that with the PL schematic vs what I found installed. May have been a mistake of a previous tech, not sure.

I plan to eventually do a full WOPL conversion. Starting little by little.

 

[grapplesaw]

I’d suggest you upgrade the 2.3k 5 watt resistors to 7.5k 5 watt and change the ic’s to lf351 type

here is the PL doc

 

[SG700II]

I’d suggest you upgrade the 2.3k 5 watt resistors to 7.5k 5 watt and change the ic’s to lf351 type

here is the PL doc View attachment 81717

I read about this in another site, but did not have all the info this bulletin gives. Thank you. I will consider it, however I already ordered the 2.4kohm. Perhaps in a few months, but then again, im going to eventually do WOPL.

 

[wattsabundant]

Attached is the service manual. see the bulletins. It wouldn't hurt to add a small electrolytic cap, say 100uf/25 volt and a 0.1uf film cap in parallel with the zeners.

 

[SG700II]

I’d suggest you upgrade the 2.3k 5 watt resistors to 7.5k 5 watt and change the ic’s to lf351 type

here is the PL doc View attachment 81717

Attached is the service manual. see the bulletins. It wouldn't hurt to add a small electrolytic cap, say 100uf/25 volt and a 0.1uf film cap in parallel with the zeners.

Ordered the caps, opamps, 7k5 5w resistors.
Thank you

 

[mlucitt]

Phase Linear chose to reduce the control board voltage from 100V to 15V with large power resistors and Zener diodes. This is not optimal as shown by the "browning" of the circuit board. The White Oak Audio Rev G1 Control Board uses two +15V and -15V precision power supplies (dedicated power transistors with large heat sinks fed by voltage regulators and Zener diodes) for each channel. This ensures the OPAMPs and other related components have constant and reliable DC power available regardless of supply voltage or circuit loading.

 

[J!m]

“Using what we refer to as… the right way…”