Kicker zr600 blowing fuses

[claff]

Ok so this amp has been sitting around for a while, basically when i turn the remote wire on it powers up but then blows all 3 internal 30A fuses immediately. ive done this twice now.

I dont know a great deal about the inner workings of the amp but i know how to use an iron and multimeter and know a bit about electrics.

Where should i start looking first as it appears theres a short in the power supply somewhere, maybe because the amp has been sitting for ages. because its an old school amp should be easier to work on.

also there are pics of the amp here: http://ampguts.realmofexcursion.com/Kicker_ZR600/


any help MUCH appreciated,

[Perry Babin]

It likely has shorted output transistors. If you're unfamiliar with amp internals, read through the basic amp repair page below. If you have specific questions after that, let us know.

[claff]

OK i'll have a look tomorrow. thanks mate

[claff]

So I had a look and read pretty much everything on your site to do with amp repair (helpful). there are some that have item number RFG70N07 which are the power supply FETs i think, on the audio end there are TIP35C and some TIP36C as well.

there is no visible damage to the inside of the amp.

what tests can i run to determine which transistors are shorting if that is the case. I've read your section on testing transistors but don't I have to actually remove them from the board to do those?

Thanks again

[I Am An Idiot]

In some cases you do have to remove a transistor from the board to test it. In your case, you should be able to identify the defective channel without removing them.

[claff]

The amp runs with 4 tip35c and 4 tip36c per channel. Theres a dead short between collector&emitter on one of the tip36c which is a PNP bipolar junction transistor.

There aren't any total shorts on any of the other transistors. Although i get some odd low readings like 22 ohms which shows between the outer legs on all the other transistors I suppose this might be because theyre in parallel with the defective one?

I take it i need to buy a few of these tip36c and once theyre fitted the amp should work?

[Perry Babin]

If the meter tells you that you have 1 shorted output and it's still in the board, you also have at least 1 open emitter resistor.

You MUST replace all 4 of the TIP36s in that channel. I'd also recommend that you replace the TIP35Cs in that channel. If you have one open emitter resistor, you must replace all 4 that are connected to the TIP36s in that channel.

I'd recommend On-Semi brand replacements for the 35s and 36s.

The 22 ohms is the base-emitter resistor.

Generally, if you remove the shorted transistor, the amp will operate normally if there is no other damage. If you try this, clamp the transistors tightly to the heatsink before applying power. I'd recommend that you also insert a 15 amp fuse in the B+ line before applying power.

[claff]

I'll remove the bad transistor and try powering it up like you said tomorrow.

But for now I'm testing the emitter resistors and ALL of them read 0 ohms apart from the one on the shorted transistor which reads 441 ohms. What does this mean exactly?

[claff]

Oh and also i'm in the UK so I dont think on-semi can deliver to me, also I couldnt find any of the 36c/35c using their search function.

I found some on flea bay though have a look (they also do the 35c): http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=014

they do 5 of them for a few quid less but I think i'll get 10 of each so I can cherry pick them for perfect matching. Just wondering if anyone had any opinions or alternative suggestions as I'm wary of buying fake parts, but this seller seems legit.

Thanks again for all your help, Perry

[Perry Babin]

What about Mouser UK?

441 ohms means that it's defective, These are the resistors I'd recommend.