Parasound HCA-3500 Upgrade & Question

[hamrules]

I'm trying to find if anyone has done the modification listing that is on the Interweb as I am trying to verify one item. It says to remove capacitors in R71 - R76, R79 & R80 locations which is fine but no mention of replacing them with the resistors called out in the schematic.

 

[hamrules]

I’ve cut the area in reference to the resistors and circled them in red. They are all listed as a 10K @ 1watt.

 

[whoaru99]

...

 

[hamrules]

Wonder if that resistors should be installed. I didn’t find anything on the Interweb from anyone talking about it. I did find a nice picture from someone that did the modification/upgrade list and they are just left blank. Blank it will be.

 

[whoaru99]

I'd probably leave the darn thing alone if you're unsure about why it would be one or the other, and the reason or not to tinker with them.

What's on the board is generally considered correct if there is a difference from schematics.

 

[hamrules]

This is the list that Big Sky Audio used to do to them when they were still in business.

 

[hamrules]

One board finally done.

 

[ivandezande]

View attachment 3839803

I’ve cut the area in reference to the resistors and circled them in red. They are all listed as a 10K @ 1watt.

They're just cap bleeders, right? I don't think removing them would be good.

 

[hamrules]

They're just cap bleeders, right? I don't think removing them would be good.

Yes I agree but Parasound had caps installed in those locations which BigSky said to remove. BigSky does not say to add the resistors that show in the Parasound schematic back in. Right now I have the one new cap installed like they say in the modification list.

 

[hamrules]

Right side & power supply board out, looks empty.

 

[hamrules]

Power supply board done. Re-soldered all the wire screw posts to make sure they were good and re-enforced. Couple of new 50amp bridge rectifiers and a larger heatsink of copper that is sandwiched between the bridges and the chassis.