Yamaha CR-1020 power supply mod?

[Gigapod]

Hi,
This is a question for the Yamaha CR-1020 experts: I read there is a mod that has to be done in the power supply to prevent the speaker output relays from turning off the sound annoyingly.
Anybody has any information on what the problem is exactly and what mod is necessary/recommended?
I just indulged and ordered a CR-1020 from that place...
Thank you all!

 

[merrylander]

First I've heard of it.

Rob

 

[mhardy6647]

I hope that the significance of Rob's reply isn't lost on the original poster

 

[merrylander]

I do run the same service bulletin mods on 1020s as I do on 2020s, except that I do not change the regulator transistors, the 2SD234 is adequate for the 1020. I have seen an added resistor on the foil side of the board, they generally tend to look as if they have been cooked a bit and removing them has no effect.

Rob

 

[Nakdoc]

The regulators heat cracks the solder. I suppose a mod might include larger heat sinks? There is a bulletin to change both 0.01 uf disc caps behind the 2 heatsinks. Some people replace the connector to the cap board if the plastic is brown and cracked. Digi Key still stocks this connector.

 

[Gigapod]

Thanks Rob,
And of course I know your reputation and admire your patient, detailed work on Yamaha receivers, so your advice and experience is more than welcome.
Thanks, Nakdoc, I'll change the disc capacitors and check the heatsink and surrounding solder joints.

 

[merrylander]

Nakdoc's suggestion of better heatsinks is good, just measure the room above the board and if you put in bigger ones I suggest that you use the mica insulators. As they come from the factory the sinks are at 50V DC potential, one positive and one negative - that's why they are glued down.

Rob