Can anyone give me some insight into this. The power switch is sticky. I have sprayed it with contact cleaner on A few occasions and it would work for A short time and would stop. Some days I can't power on and others I can't power down. Do I need A new switch? Should I take it apart and see where it's getting hung up? Just curious if anyone has run into this. Thanks for any feedback.
Last edited:
Since it doesn't work right, you may as well disassemble the switch and see if it can be repaired.
A mechanically compatible replacement could be difficult to find.
A mechanically compatible replacement could be difficult to find.
That makes sense. I had thought of trying that. Wasn't sure if anyone else had a similar issue. Thanks for the feedback
Great. Thank you. I may have had the part number wrong. I just found power switch on A parts list.
I spoke with Rotel parts. They do not have the switch any longer. Amp is too old and not supported. Can a switch be repaired? Wonder If I need to puchase another unit being sold for parts that uses the same switch. Quite a few from that line do. Thanks for any feedback.
Sometimes a switch can be repaired. You'll have to remove it and check.
Or just keep it the way it is.
Personally, I plug everything into a switched outlet strip and only switch that.
Or just keep it the way it is.
Personally, I plug everything into a switched outlet strip and only switch that.
Is it a "2-stage" switch? The first stage would be ON, and then the second stage would be OFF, all regulated by a small piece of wire that glides on top of the switch, inside a plastic groove (part of the switch housing), that allows for the ON -> OFF action, and then ON again.
I suppose you could take a photo of it... that would be a good start to confirm the above Disassembling the switch is not much of a problem... usually, the plastic guide groove wears off... and then the switch exhibits exactly what you described.
I suppose you could take a photo of it... that would be a good start to confirm the above Disassembling the switch is not much of a problem... usually, the plastic guide groove wears off... and then the switch exhibits exactly what you described.
I tried it with a power strip. It has a 2 stage turn on process with the button. Didn't sound very good when I tried the power strip.
I agree that repair or replacement of the power switch is the preferable solution.
But if you get stuck, I have a thought. By way of exploration, was behavior with the power strip objectionable at turn-on or more likely at turn-off?
Thanks.
But if you get stuck, I have a thought. By way of exploration, was behavior with the power strip objectionable at turn-on or more likely at turn-off?
Thanks.
More when turning on. Just seemed like a quck pop and didn't sound right. Not a pop in the sense of blowing anything, just abrupt. Was trying to find a way to install a 12V trigger and then realized I am not equiped to even entertain the thought. I switched over the the 5 ch Rotel amp I have and let the other sit until I figure something out. I plan on taking it apart tomorrow. Thanks for the help!
I confess it surprises me that the turn-on transient is worst.
I'm woking from solely from the schematic, so I could be overlooking something. But it appears that there's delayed turn-on established by R13,C14 in concert with T11, T12 and relay RY901. Delay of relay would be very roughly 2 to 3 seconds from plug-strip activation. There may be additional delay arising from the protection ICs, but I haven't studied those circuits yet. When you open the amp, you might look for these delay features.
The work-around idea I was alluding to is to the leave the small transformer (T101) permanently powered, and use an odninary spst front-panel switch to switch B+ to the delay circuit, i.e. switch installed between connectors K104 pin 1 and K13 pin 3.
Good luck.
I'm woking from solely from the schematic, so I could be overlooking something. But it appears that there's delayed turn-on established by R13,C14 in concert with T11, T12 and relay RY901. Delay of relay would be very roughly 2 to 3 seconds from plug-strip activation. There may be additional delay arising from the protection ICs, but I haven't studied those circuits yet. When you open the amp, you might look for these delay features.
The work-around idea I was alluding to is to the leave the small transformer (T101) permanently powered, and use an odninary spst front-panel switch to switch B+ to the delay circuit, i.e. switch installed between connectors K104 pin 1 and K13 pin 3.
Good luck.
The power on delay of speaker activation seems to be handled by uPC1237 chip (datasheet available in internet).
To increase the power on delay you need to add capacitance on pin 7 - quite easy to test.
The delay may be too short for the output to stabilize - when you put a digital scope on the output before the relay then you will probably see something like this:
I have been forced to increase the delay from 4 seconds to 7 seconds on some amplifiers.
I will investigate this. If you think just using the power strip with its power switch is safe, that might be my option. I am going to take it apart today. If anything needs to be changed, I am not sure I am capable but maybe with some guidance. I am an RN and not an electronics tech. I do most of the work around the house and cars including some more complex tasks I will seek to do it myself because if I can, why not. I just need to know my limits. Worried about soldering on a PCB board if that is necessary. Thank you for the input.
You should also check that there is no DC on the output. If DC is present then adjusting the delay will not solve the core problem.
Well, you cannot do really anything (in this forum scope) without soldering 🙂
If you are not confident in your soldering skills then the only solution is training - get hold of some some broken gear from the same era (i.e. through hole components, not SMD) and just spend a day or two on removing the parts and soldering them back again. It is just manual labour skills, no spaceflight involved...
Good idea. Yeah I have seen it done countless times.May not need additional solder from what I have seen. Just heat up enough to remove and back again. I'll try it. This is a DIY forum.
I would advise always removing old solder as well as possible (with wick) so that you can remove the component that should be pretty loose in that stage.
When soldering in a replacement component fresh solder (the one you know and are comfortable working with) should be used.
That isn't the way it should be done. It does take a lot of skill to make it look easy.
Definitely practice a lot first, with the proper equipment.
madis64 offers great advice re confirming no DC on speaker terminals. With luck, you'll confirm there's no amplifier fault.
There's a lot of troubleshooting you can do without needing a soldering iron. It's worth exploring why the plug strip seems to behave differently than the amp's power switch. It appears there should two stages of delay at power-on: the relay RY901 energizing after about 3 seconds, then additional delay controlled by the protection circuits. I believe these elements should dwarf mechanical behavior in the power switch, be it front panel switch or a plug strip. IMHO, electronic elements should control the turn-on behavior; power switches should only set things in motion. You can open the case and listen for two stages of relay activation. Assuming that power sequencing is as described, there may be a simple fix.
There's a lot of troubleshooting you can do without needing a soldering iron. It's worth exploring why the plug strip seems to behave differently than the amp's power switch. It appears there should two stages of delay at power-on: the relay RY901 energizing after about 3 seconds, then additional delay controlled by the protection circuits. I believe these elements should dwarf mechanical behavior in the power switch, be it front panel switch or a plug strip. IMHO, electronic elements should control the turn-on behavior; power switches should only set things in motion. You can open the case and listen for two stages of relay activation. Assuming that power sequencing is as described, there may be a simple fix.