PS GRD's used for all measurements. The pair of GND pins for the +/-60V ... and the GND pin between +/-15V for those voltages and the +24V reference.
I just asked the question because the PS and chassis ground is done through a 10 ohms resistor. That it is OKAY. What happened with the capacitors? Did you was able to locate some? I forgot to tell you that the reason it is slowing when reading in AC because the meter is reading a low voltage. It is normal. Now we have to concentrate in the +15 volts.
Had to order them ... they'll be here Tuesday.
Thought I'd check the rails under a load and everyone of them fluctuates except for the -60V.
Pretty sure I can recap this without pulling the board out. Rane cautions against removing the PS module in the schematic header. Only reason I can see is their fear that nothing will line up "just right" if it gets removed ... nah, that can't be why. Screw tolerances aren't that loose. Maybe too fragile???
Anyway, a guy can take amp card 1,2,3 out and have good access to the PWR module. Chassis up on end so board is secure.
Thought I'd check the rails under a load and everyone of them fluctuates except for the -60V.
Pretty sure I can recap this without pulling the board out. Rane cautions against removing the PS module in the schematic header. Only reason I can see is their fear that nothing will line up "just right" if it gets removed ... nah, that can't be why. Screw tolerances aren't that loose. Maybe too fragile???
Anyway, a guy can take amp card 1,2,3 out and have good access to the PWR module. Chassis up on end so board is secure.
We need to wait until Tuesday.
By the way check my thread in a project I am working on. Check thread number 6 at the bottom.
http://www.diyaudio.com/forums/chip-amps/209519-protecting-speaker-output-using-microprocessor.html
By the way check my thread in a project I am working on. Check thread number 6 at the bottom.
http://www.diyaudio.com/forums/chip-amps/209519-protecting-speaker-output-using-microprocessor.html
My advised is do the job by steps. If you replaced too many components and something goes wrong you will not be able to determine what caused the problem. lets make sure that by replacing the caps for the +15 fix the problem then go ahead change the other caps. I will replace all the electrolytic capacitors in the power supply later. If you want you can order the capacitors but lets change what it is causing the problem right now.
Took the old ones off the board .... leaking around both + legs underneath. Now I'm wondering about the rest.
Did changing those caps fix the problem?. after fixing the problem, I would upgrade most the electrolytic caps.
I would change both +/- 15 volts first. Because this where you have the problem. Then if everything worked out OKAY proceed to change the others one. Do not forget to mark the polarity of the capacitors. They a polarity. Most of them have a band indicating the negative side. After replace them do the AC check and DC test to make sure they match.
It is fixed. The amp is absolutely quiet .. no hum/buzz. The turn off transient is nonexistent .. no pop/thump.
At first I thought I'd stuffed up the repair somehow
... nope .. this is most excellent!
I could not have done this without your help, guys. Everyone that posted including Mike, Mooly and especially you tauro0221 ... you fellas are the best!!
At first I thought I'd stuffed up the repair somehow
... nope .. this is most excellent!I could not have done this without your help, guys. Everyone that posted including Mike, Mooly and especially you tauro0221 ... you fellas are the best!!
For now just the (2) 15V circuit capacitors were swapped out. PACCOM 85*c replaced by NICHICON 105*c.
I'll be checking/replacing the other caps later for sure. As tauro0221 and Rane's tech's say .. there should not be any AC ripple on the rails. Was powering down unevenly causing the relays to lag. Found out that the amp was born in 1996. Has never been serviced.
I also asked about the single resistor (only on the -60V rail) Ranes response:
"The extra resistor on the one side (but not the other) of the power supply is all about balancing the load to the supplies (under normal operating conditions).
One side of the amp output is always grounded (otherwise bridging pairs of channels would not work). So we simply keep that side grounded all the time - even when powered off. This is helpful in the safety and NEC sense in constant voltage systems and certain jurisdiction such as Las Vegas and Chicago where they're anal about grounding systems - especially with all the cable types being run through plenums."
Rane has some pretty nice people working for them too.
I'll be checking/replacing the other caps later for sure. As tauro0221 and Rane's tech's say .. there should not be any AC ripple on the rails. Was powering down unevenly causing the relays to lag. Found out that the amp was born in 1996. Has never been serviced.
I also asked about the single resistor (only on the -60V rail) Ranes response:
"The extra resistor on the one side (but not the other) of the power supply is all about balancing the load to the supplies (under normal operating conditions).
One side of the amp output is always grounded (otherwise bridging pairs of channels would not work). So we simply keep that side grounded all the time - even when powered off. This is helpful in the safety and NEC sense in constant voltage systems and certain jurisdiction such as Las Vegas and Chicago where they're anal about grounding systems - especially with all the cable types being run through plenums."
Rane has some pretty nice people working for them too.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.