Monster Power HTS 5100 MKII Power Center

[ggil44]

Hello, I have a Monster HTS 5100 MKII Power center I am having trouble isolating the short circuit. On the primary input board I measure 0 ohms from the power to the neutral and 0 ohms from power to ground. I tried removing the transformer because I heard that has been a problem but it made no difference. There were some traces on the circuit board that were melted and open so I re-soldered jumpers to reconnect them again (see area circled in yellow). Prior to that the HT-5100 power center would just flash a light labeled “Abnormal Voltage”. I am enclosing some pictures and would greatly appreciate any advice you can offer.

[ggil44]

Re: Monster Power HTS 5100 MKII Power Center

Is there anyone that can offer some help with this? Thanks

[momaka]

Re: Monster Power HTS 5100 MKII Power Center

For starters, I see lots of the infamous tan/brown glue that goes conductive over time, under the big transformer and the aluminum heatsink on the board. So first order of business would be to remove that glue - all of it. Chisel away with a flat screw driver, but be careful not to damage traces or nearby components.

Next, check diodes D15, D16, D27, and D28 - they look a little faded / overheated and might be shorted. R27 looks like it has seen a little more power than it should and should be checked as well for abnormally high resistance or open-circuit (best to do with one leg lifted or completely out of circuit.)

Could we also see what's under those purple fire-proof cloth bags? I see designators M1, M2, M3, and M4. MOVs? Relays?

Lastly, can you identify / get the part number(s) of the two 3-pin components mounted on the aluminum heatsink?

[ggil44]

Re: Monster Power HTS 5100 MKII Power Center

Thanks for your help and suggestions. I will take your suggestions and try to identify the components you asked about. It may take a day or two as I have a few other irons in the fire. Regards,

[ggil44]

Re: Monster Power HTS 5100 MKII Power Center

Hello, thanks for the suggestions. I tried to “chisel” away the glue. (didn't know it goes conductive).
Checking D15, D16, D27, D28 on the diodes in circuit gave readings of .584 to .592. Resistor R27 gave a reading of 33.48K ohms in circuit and 33.48K also with one leg lifted. I am including some pictures of the circuit board without the cloth bags.

[Unspun01]

Re: Monster Power HTS 5100 MKII Power Center

Check your soldering on the burnt trace repairs. Some of those re-soldered connections look a little close for me from the photos. Also, check ALL diodes for shorts. Not sure what happened, but any silicon rectifiers may have experienced over-voltage and may be shorted even if they don't look bad. Also, check the heat sink mounted ICs for shorts between pins in any combination. Sometimes if it is a diode, pins 1-3 are same and may measure 0 ohms which is ok. Check pins 1-2 and 2-3. One is a 7805 5V regulator and should not have shorts between any of the pins.

[ggil44]

Re: Monster Power HTS 5100 MKII Power Center

Hello Unspun01, Thanks for your suggestions and help. I replaced my trace repair, I used a high gauge wire because I didn't think the traces would carry much of a current load. I also found D12, D13, D14 to be shorted. The rest of the components I found to all have resistance. Please see pictures. Regards,

[Unspun01]

Re: Monster Power HTS 5100 MKII Power Center

Check R27 also. Looks like 220 ohm red red brown. Looks stressed.

[R_J]

Re: Monster Power HTS 5100 MKII Power Center

The shorted diodes are like what burnt the traces, once they are replaced the power supply might be fine. R27 is a bit discolored but is likely ok as well, they can get discolored over time due to heat but replace it if you like.

[ggil44]

Re: Monster Power HTS 5100 MKII Power Center

Thanks for the help! I did check R27. Resistor R27 gave a reading of 33.48K ohms in circuit and 33.48K also with one leg lifted so I think it is OK. Yes, I am wondering if the bad diodes are a result of another failed component I haven't discovered yet. Regards

[ggil44]

Hello again, I received the diodes in the mail and soldered them in place of the shorted ones. I crossed my fingers, legs and arms and plugged it in. No immediate short, hooray! then the relay kicked on and immediately back off. So I started unplugging circuits and found that controller board was the problem. With the controller circuit plugged in, I unplugged each of the circuits plugged into it until it was just the controller board with no external circuits plugged into it and the relay switched on then immediately back off. My guess from here is that now it could be the controller circuit but it still could be the controller board is still finding fault with the power board. The controller board has 2 removable IC's and I am really hoping they are not the problem because I wouldn't know how to program them even if I could.

[dudaindc]

Any progress on this repair?
I have a similar unit that is half working...

[ggil44]

Hello dudaindc, The best I could do is get it to work for about 5 minutes but then faded back to power on, self test, power off. I pulled the "D" chip on the controller board for it to work for the short time it did but obviously it wasn't the root problem. I have since written it off because it is above my technical know how and the test equipment I have to repair. Sorry I can't be of more help. Regards

[momaka]

Hey all, sorry I didn't follow up with this thread. Looking back at it, I notice many of the small electrolytic caps are not really any good brands that I recognize. As such, I do recommend also checking all of the small (and large) electrolytic caps too.
Also, all of those components labeled M1, M2, M3, and etc. indeed seem to be MOVs, and between them are thermal fuses labeled with TF1, TF2, TF3, and etc. I can't really trace out the circuit given the above pictures, but perhaps there's a chance the controller(s) check if there's an open thermal fuse (due to a possibly bad MOV, or just a bad thermal fuse on its own) and shutting down as a result?

dudaindc: can you post more info and pictures in regards to what your unit is doing?