kicker kx 650.4

Information requested:: The rectifier is marked RFE or possibly RPE,KBU-1004 AC. The 2 large capacitors are 1500uf\200v. I'll check the voltage on the 740's and post tommorow?,today? You know what i mean!I've noticed one thing about "Experts". When one shows up,someone gets hurt!

Thats a 400V/10A full wave bridge, with the AC input on pins 2/3. Here's the sheet... Only rated to 150°C, WITH a heatsink, it may still be the offender. OK... 2-3 voltage should be 120VAC. 1-4 voltage should be about 170VDC. 1-2 voltage COULD be zero or up to 340VDC, depending on whether pin 2 is neutral/ground or the AC hot leg. Same parameters apply for 3-4. The caps (and I am speculating based on their values) are likely wired in series with a center tap, so you have two rails. A 0V reference, (the tap leg between the caps) a -170VDC, and a +170VDC. This is where your 340VDC reading came from in your earlier post. These are the DC voltages that are chopped to feed the primary side of the transformer. I also noticed three lugs on the output side... Two positive, and one ground? Re-reading your post with the measured voltages, there MAY be some sort of doubling going on in there... With the cap on the input side (the yellow one), it could happen. I'll want to see pics of the underside, but those numbers don't sound right.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Got the pics you sent me. Seraching the web got me to this forum, where in the second page of that thread there is a large backside photo of the very PS we are examining. I am one of the last people ever to say "It's a loss", (I generally love a challenge) but with all of the control circuitry, the high(er) frequency choppers, the lack of an o-scope... This one might be a loss. My suspicions were correct, however. It's a dual rail ±170VDC power input to the low voltage side. The large transformer is the step-down from the switcher (chopper), the four transistors to the upper left on this thread's picture are the choppers, the four diodes to the upper right are the rectifiers for the 12V output. This, sadly is about as far as I can go... i am, you're up! There isn't much filtering happening there... Those are pretty small caps for ripple control, and the inductors, being iron core, won't be really effective until higher end currents are reached. If you get this fixed, what woould you want to use it for? It's gonna be really noisy...It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

It will be used for 12vdc lighting and to charge the auxillary battery's,if repairable.If not,it will become a small boat anchor.If it's up to the task!!!I've noticed one thing about "Experts". When one shows up,someone gets hurt!

I went back thru the preceeding post and hopefully this will get us back on track. The dc voltages on the 740's, I checked these both ways: Blk lead to ground of incoming 120vac,and to the 12vdc ground.Red lead to the metal tabs of the 740's.Just making sure everything is as it should be. #1 167vdc. #2 167vdc. #3 -1.9 to -2.1 #4 -1.8 to -2.3 Last test: Blk lead to tab of left 740,Rd lead to tab of right 740 on the end = +7.1 to +8.3 vdc unstable.Reversed leads and readings were the same,but negative. Full wave rectifier... Post 2 and 3=+120vac. Post 1 and 4=+340vdc. Post 1 and 2=+167vdc. post 3 and 4=+167vdc. 2nd post is 120vac hot. 3rd post is 120vac neutral. If i read previous post correctly: Post 1 and 2 should have rendered 0volts or 340vdc. Post 3 and 4 should have been 0volts. Post 2 and 4 rendered 167vdc just in case it was needed. The discoloration or heat marks on the back side trace: The component in question is a diode marked D-13.The discoloration is not as severe to the other side of this diode,but the trace goes to a socketed chip marked 393N. I've noticed one thing about "Experts". When one shows up,someone gets hurt!

I would try replacing the comparator it is an LM393  or an NTE 943M. 

Looks like a simple changeout.But,looks can be decieving? Heat sensitive?How does the socket help with parts that overheat? Any other parts that may have toasted downstream? I don't mind purchasing maybe's. The freight is generally more than the cost of parts. Oh Yeah, Thanks again for your time and effort.I've enjoyed the experience!.....I've noticed one thing about "Experts". When one shows up,someone gets hurt!

The sockets have nothing to do with heat.  When they notice that a part is failing more frequently than they expected it to, they mount it in a socket so they can pay some rookie minumum wage to change the part out.  If that fixes the unit they ship it back out.  If it does not, then they send it to the technicians for more troubleshooting.   Search for the other chips using the numbers on them.  Let me know if you can not find info on them.