Auto power on problem with Paradigm PS1000

[william13]

ah, you had the lamp, the 68v with the lamp make sense. the 12v missing should be on the lamp. You was tellling me that the fuse was ok without lamp so i though it was directly

The 68 is both with and wo lamp , I did that experiment after I removed the resistor which shut off the relay

 

[william13]

No no, just check voltage if you have +-4 v. that's all

Ok I will do that but what do you think about c105 being a 22 uf capacitor but reads 800 uf. Wondering it this caused relay to buzz and rapid on off on off of current blew fuse.

So I just did a ton of reading on buzzing relays. Not uncommon. Typically relays have both capacitors and diodes in their local circuitry. The capacitor allows the controlled closure of the relay when current is withdrawn. I am betting this is my issue. So I am going to contact digikey for this c105. But should I replace of bunch of components for the heck of it rather than just ordering a 15 cent capacitor?

 

[Yannick99]

I may have found something! There is a capacitor (C105) with a 22 uf rating but when I test it, it reads 800 uf! This connects to the relay. Wondering?

800uf very not normal but not sure it's your original problem. you must replace it and see what happen.

 

[Yannick99]

My mind is more normal this morning than Friday night lol If the capacitor is 800 instead 22uf this one should be very leaky (electrically) so yes it can short-circuit the coil and put this one in oscillation.

 

[william13]

and blow the fuse right?

 

[william13]

So, I tested my bridge over and over and it tests fine ....yet the 68 v across dc without lamp or load.
From my understanding if one of the 4 diodes blow or fuse the others will follow. I will test my Fluke to see if its accurate. I am curious about your ps1000. Did you recap it just for the fun (I mean the small caps not the filters). I mentioned this last nite when we were all comatosed but I was thinking that since I have this apart maybe I should replace things that might go in the near future. Things like the bridge and the other small caps like the c105. But the c 105 is special because I it is located right near those hot fuses that everyone has issues with so maybe I just spend 25 cents and call it a day. What do you think other "normal" hobbiests do?

 

[Yannick99]

Did you recap it just for the fun

On mine i just replaced the 2 resistors. That's all. On your side, if you have found an defective electrolytic capacitor, maybe it should be a good think to recap the the whole thing. Normally electrolytic doesn't age well. For the other part, no need to replace anything. Normally ceramic and other cap (except paper) age well.

But before to do that, you should find the real problem. If not you can buy a lot a stuf and the problem can be still there and spend money and time for nothing.

Your fluke is ok. if 4 diode are fine, the bridge is ok. Maybe the 68v is normal and the schematic is wrong. Put your dmm in ammeter (in series) How Amp do you read ? If the reading is low, you do not have a short anymore.

Have you reinstall the mosfet ? do you have sound ?

 

[william13]

So when I removed the resistor to the relay, the units obviously quieted down. I used up all my 5 amp slow fuses (like 5). So I put a 3 amp in and it did not blow. I will put back the mosfets today. I believe I still have to short those other 2 transistors so I can get power on. One thing I do not understand is why my toggle switch does not turn the power off. I get 68 v no matter what its position is ON off auto on i will let you know the amps

 

[william13]

Ok....First mishap! While putting back mosfets and tightening bracket I broke a screw and it took me an hour to get out. So when I get replacement screw I will get back

 

[william13]

Would you know where to source those Mosfets
morocco
There are 4 types of mosfets in this subwoofer
ST 9627 tip 36 C
ST 9727 Tip 36 c
ST 9701 Tip 35 c
st 9548 35 c

there are 2 of each. When I go to digikey and mouser I see tip 36 c and 35 c but I do not see the 4 numbers like 9627 and 9727 and 9701 and 9548

 

[Yannick99]

Hi too bad for the screw... you need to replace some mosfet ? I thought it was all good ?

my first source for me is Digi-Key and mouser. But often, old part are discontinued. In this case I try ebay. But problem with eBay you are never sure what quality you will have. Good, doa, fake...

Another thing you can do is find a replacement equivalent mosfet. Active and in stock.

Now, 9627 9727 is not important. It's just a date code or something. The part number are tip36C and tip35C. You can also found this info in datasheet. Q1 to Q8

For your switch it's normal, you bypass r184 r185, it's always power on.

Try to resolder everything. replace c105 and see what happen.

 

[william13]

One broke.....Its the middle lead so I can put a new leg/limb on it but when I went to look for a new one I could not find those 4 digits after the 35 and 36 c I am wondering if there is only 35 and 36 c and those 4 digits do not matter.

https://www.mouser.com/datasheet/2/389/tip35c-1852460.pdf

I think you are right about the 4 digits but the weird thing was that whoever put this unit together made sure each 4 digits were aligned with each other left and right ie (see my picture below)

 

[william13]

Photo below

 

[Yannick99]

Yes it's just tip 35 36 both Complementary device npn pnp. Other number are not important. And it's not mosfet but transistor.
Very easy to test with dmm. You can replace the broke one or just put a wire for now.

 

[william13]

RIGHT BIPOLAR JUNCTIONAL TRANSISTOR ....THANK YOU FOR ALL YOUR HELP. TOMORROW I WILL PUT THESE BACK IN WITH REPAIRED LIMB. I WILL KEEP THE RESISTORS SHORTED AND THE PULLED ONE WILL REMAIN OUT. I WILL SEE IF IT IS FUNCTIONAL. I really appreciate all the time you gave me.

 

[william13]

Stand by ! All parts to arrive this week

 

[william13]

Update:
I replaced capacitor c-105 which more or less stabilizes voltage changes to the relay. The buzzing of the relay immediately stopped. The DC voltage from the rectifier became 80v as in the schematic.
The fuse which temporarily a 3 amp (ran out of 5 amp) did not blow. When I throw the toggle switch into different positions ie always on, signal on, always off....you can hear the relay click with each positions change. I have not fully put it all back together yet because I have big plans this weekend.
I splurged for the Hakko f301 and I bought all new capacitors and a few new bipolar junction transistors. So forgetting the cost of everything else I bought a $.12 component fixed this unit. I want to thank you Yannick99 for your guidance and patience. So this is another reason fuses blow on this unit. Who knew a very small capacitor that regulated the relay. Hopes this helps others.
BK

 

[william13]

Yes it's just tip 35 36 both Complementary device npn pnp. Other number are not important. And it's not mosfet but transistor.
Very easy to test with dmm. You can replace the broke one or just put a wire for now.

Just realized I never replied directly to your kind insight. Thank you. I am on the right road now I believe!


FYI: every single electrolytic radial capacitor was bad by DMM and ESR meter. I recommend complete recap for these units that are 20 years old.

Put it all back together
No buzzing, no hum, the auto off/on works fine
sounds great.
Thanks for all the help

 

[Tagfu222]

New here.

I have an PS-1000 for 120 volts with no version number made on 11/16/1994. My circuit board does not look like any of the pictures in this thread.

I obviously have something burned out, but have no idea what or why.

Any help would be greatly appreciated.

 

[Yannick99]

Just realized I never replied directly to your kind insight. Thank you. I am on the right road now I believe!


FYI: every single electrolytic radial capacitor was bad by DMM and ESR meter. I recommend complete recap for these units that are 20 years old.

Put it all back together
No buzzing, no hum, the auto off/on works fine
sounds great.
Thanks for all the help

Sorry for the delay, never received an email to tell me you had answer. Your welcome. Glad to see it's working fine

 

[Yannick99]

New here.

I have an PS-1000 for 120 volts with no version number made on 11/16/1994. My circuit board does not look like any of the pictures in this thread.

I obviously have something burned out, but have no idea what or why.

Any help would be greatly appreciated.
View attachment 1391320View attachment 1391322

You have a regular ps-1000
Look like a capacitor just blow Maybe the diode too.
Look the datasheet, it's probably c34 or c15. it's 1uf. Replace both
Diode doesn't looking good too. there are 1N5402. Test it and replace it.

Check for a short somewhere.... Check capacitors etc..

Yannick

 

[william13]

The only thing I can add is that every small capacitor on my board was bad/weak so this is a good time to replace. The large filter capacitors typically are good. The mosfets typically are good. The diode recitifier needs to be checked. (google its easy). When I replaced some of my large resistors I kept them a few mm high off the board.

 

[B3all9]

Hello all,
i followed the advice of a few people on this forum and replaced the resistors and the fuse. It worked! Just join the two resistors at the bottom instead of relying on the circuit board. That’s where there’s carbon tracing and damage from excessive heat. I left the wire a little longer at the bottom on both resistors and soldered them together. Also, I went from 2k 3w to 2k 5w because that’s all I could get my hands on. The resistors were larger but still fit. The fuse didn’t need replacing but I did it anyway with the same value and type. All good now. An easy fix. Thanks everyone for their advice.

It still working good with those 2k 5w resistor because I have the same problem like you I can’t find those 2k 3w and I really want to fix my sub ps 1000

 

[william13]

Glad to hear your success. Yannick 99 was very instrumental in the rehabilitation of my unit.