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Old 3rd September 2006, 12:38 PM   #1
kdawg is offline kdawg  United States
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Default Carver PM1.5 Ticking

Hello - I've been reading through some of the threads here but haven't quite found a solution for this Carver PM1.5 I'm working on.

The amp has a low "ticking" sound that's audible in the speakers and from I believe the power transformer. Fans barely move at this point either. Signal passes fine other than that in both channels. No protection light on.

Here's what I've tried:

1. If I set RP1 power supply to minimum, everything is OK. Fans full speed, no ticking. As I ramp it up, the fans slow down and ticking starts.

2. I've replaced the triac, diac, diodes, and caps on the regulator board just in case, no change.

3. I replaced OC1, no change

4. I've checked all the power transistors and they all seem OK, but I'm not 100% sure because I had a suspect ohm meter.

5. I have a variac to check things and I have a scope. I can get readings, but I'm not sure where to start.

I'm using the Carver Service Manual PM1-5, which they kindly emailed to me.

Thanks for your help
-kdawg
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Old 3rd September 2006, 01:15 PM   #2
anatech is offline anatech  Canada
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Hi kdawg,
Quote:
1. If I set RP1 power supply to minimum, everything is OK. Fans full speed, no ticking. As I ramp it up, the fans slow down and ticking starts.
Man, you almost made that amp into a nightmare repair!!! Read your manual, then read it again until you understand it.

You can not begin to repair this amplifier until you understand how it works. The ticking sounds like the triac is firing unevenly. Replacing the triac, diodes and optocoupler would not have helped in this case.

The dual capacitors can do this. I assume that you've replaced those from your comments. Did you check the resistors in the voltage regulator section?

If you can not trust your equipment, replace it. A Fluke is the best handheld meter. Most others are worthless in comparison.

-Chris
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Old 3rd September 2006, 05:32 PM   #3
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Default PM 1.5

Anatech is absoulutly correct, these amps are class H and switch between three power rails to decrease dissipation and increase overall efficiency. You dont want to take your carver amp into your local TV repair shop, you will probanly end up with a $300 repair that started at as a.5 cent resistor.
As anatech stated re- read your manual and check the power regulation section, the up-right board on the left in the middle with the up-right variable resistor. There are two resistors in the feed back network the set the center point if one goes open the amp with cycle the protection circuit. I believe this was a very common repair and was later rectified by replaceing the 1/4 watt resistors with 1/2 watts and moveing them away from the large 3w heat producer.







.
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Old 3rd September 2006, 05:32 PM   #4
kdawg is offline kdawg  United States
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The amp was given to me in this condition, they had been running it for quite some time with the misfiring triac. I've never raised RP1 above the point that it was set when I got it, I know that could fry it. Since I didn't see a fault light, there shouldn't be any active shutdown protection occuring correct?

I haven't replaced C13/14 because of the dual can issue NLA. Would I be able to see on the scope across the caps if they are not keeping the DC steady?

I found these caps at mouser, would they work? (2200 uF / 63v and 2200 uF 100v)

http://www.mouser.com/search/Product...ualkey66100000

http://www.mouser.com/search/Product...ualkey66100000

Would I still have to fashion a PCB to integrate these to the power supply board?

Thanks!

-kdawg
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Old 3rd September 2006, 06:29 PM   #5
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If its ticking its a BOMB!!!!

QUICK SEND IT TOO ME!!


Sorry, couldn't let it pass.

Not to be offensive but you cannot just throw parts at something.

As mentioned earlier go thru the manual and pay attention to the power supply and regulation section. Check the board for any disscoloration of the board or the resistors. Check the current draw on the resistors and calculate to see if the resistors are indeed of high enough wattage.

Lastly, as with ANY repair work it is best done leaving the beer or mixed drink to the last therwise some spillage could occur which could lead to other that happy results. In other words you could fry your ***.
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Old 3rd September 2006, 06:44 PM   #6
anatech is offline anatech  Canada
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Hi kdawg,,
Carver used to have a replacement PCB assy. I have heard of one member installing capacitors with standard long wire leads. The snap mounts require a PCB to be made. The originals will cause all kinds of problems.

Quote:
Fans full speed, no ticking. As I ramp it up, the fans slow down and ticking starts.
That was maximum voltage. You almost blew the hell out of it.

Hi Joe,
Quote:
If its ticking its a BOMB!!!!
You are more than half right!
Quote:
Not to be offensive but you cannot just throw parts at something.
So true. Thanks for saying that.

Hi halo0925,
You sound like you've worked on these as well. You only made on error. A TV shop would write it off completely!

-Chris
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Old 4th September 2006, 01:11 AM   #7
ostie01 is offline ostie01  Canada
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This is how I put new caps in my amp.

http://img99.imageshack.us/img99/693...rcarverrh5.jpg
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Old 4th September 2006, 01:45 AM   #8
anatech is offline anatech  Canada
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Hi ostie01,
That certainly worked out well.

-Chris
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Old 4th September 2006, 04:47 AM   #9
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Default Carver's remote island guy.......The Anatech

Bob Carver would be pleased to see that Anatech is taking great care of his Carver products by offering ONLINE FREE CARVER REPAIR & Troubleshooting HELP....Where there's a fault in Carver, Anatech would be always there to Solve it....

K a n w a r
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Old 4th September 2006, 05:10 AM   #10
ostie01 is offline ostie01  Canada
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Your absolutely right, we will always need this guy's help and he is really appreciated.
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