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