Non ADA Gear > Rack Gear
Broken - Furman PM-8E Series II Power Conditioner
rabidgerry:
Anyone ever had any experience with a Furman PC breaking?
Basically the power switch lights up but the volt meter and current meter do not come on and no power gets though to any outlets.
I have made a few tests, but not a lot according to my limited knowledge.
Basically power is getting in, getting past the switch, through the fuse and gets to the main board at the back (top of the pictures). Then this is where I can't go any further.
In searching the web I came across this website
https://jestineyong.com/power-conditioner-repair/
I wonder might I be having the same issue? In which case it's the big red cap at the back.
Any advice is welcome. Thanks.
Rusty:
Hiya Gerry,
Did you check the circuit breaker ain't tripped ?
A lot of the time a poor capacitor with a high ESR reading on the over voltage shut down protection circuit can be the cause.
In many cases and also with some high power amplifiers there is a crowbar circuit = shut down = bad cap = triac has triggered and zero functionality,
Try finding a schem for this unit, and maybe I can talk you through it.
Just saying, I am not familiar with this particular piece of kit, but I'm sure it's very do-able.
MarshallJMP:
If you turn it on do you hear the relay click? If not it could be that cap. My guess is that the cap is part of a transformerless power supply to feed the relay. Also I don't think it has a crowbar circuit in it. It might just have a simple overvoltage protection circuit in that shuts down the relay. Anyway that's what I think I see on the pics.
RG, could you send me a high res pic of the back pcb so I can have a better look? I see some brown stuff on the pcb.
rabidgerry:
Yeah I hear no relay myself.
Also this unit used to turn on, but there was always a delay in actual powering up. It was like that when I got it. It was second hand of course.
Leave the hi res picture to me. I will us my girlfriends hi res camera on her phone.
Rusty:
Hi Gerry,
Looking at your pics, MJMP is correct, plus, I can’t see a triac either. There is a more basic protection circuit in place. There is no crowbar circuit in there. A crowbar is usually utilized in circuits to kick in if there is any DC component lifting up the AC voltage above a zero V center or a neutral reference and it’s not needed here in this case by design topology I would guess, so lets rule that one out as it could be mis-leading.
I cannot see enough provision for a soft-start providing the load, if there is, then it’s severely under-speced in my opinion to supply so many outlets. Then again that’s where the fault may reside. I don’t mean that this is a piece of junk by design, it is what it has been designed for, and certainly not to provide a very large switch on current capacity, but nevertheless, a good piece of equipment for what it’s supposed to be for.
I can see a zener diode in there to hold/clamp the voltage for the main big relay coil. Normally zeners are quite stable unless they get over-cooked and blow short which would lead backwards to a burned out resistor or a defunct plastic cap immediately beforehand in the design.
I cannot see brown burn stuff as per; MJMP can identify in those pics, my eyes ain’t so good these days, so please do excuse me on that one if I’m wrong.
As MJMP has said, If you could pull that circuit board up and out and take some high res pics then we could get much further and be on standby with your DVM.
Even better !!! Find a schem, or one very close model wise to this Furman series and we have the road map.
This can be nailed Gerry.
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