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Author Topic: K4600 Blew Up... maybe...  (Read 12124 times)
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jasonsmith
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« Reply #15 on: April 26, 2014, 03:57:52 pm »

Okay pulled the transistor and checked it and I think it is bad, please correct me if I'm wrong. Here are my results.

Emitter to Base = No resistance either way, just .OL (BAD)
Collector to Base = Positive on COL, Neg on Base I get a reading 4.76 something. (GOOD)?
Collector to Emitter = A reading of 4.96 (BAD) I shouldn't get a reading correct? It should just be .OL
« Last Edit: April 26, 2014, 04:14:41 pm by jasonsmith » Logged
iankellogg
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« Reply #16 on: April 26, 2014, 04:12:34 pm »

Okay pulled the transistor and checked it and I think it is bad, please correct me if I'm wrong. Here are my results.

Emitter to Base = No resistance either way, just .OL (BAD)
Collector to Base = Positive on COL, Neg on Base I get a reading 4.76 something. (GOOD)?
Collector to Emitter = A reading of 4.96 (BAD) I shouldn't get a reading correct? It should just be .OL

Are you testing in resistance mode or diode mode (does your multi meter have a diode mode)?
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jasonsmith
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« Reply #17 on: April 26, 2014, 04:14:28 pm »

Resistance mode, no diode mode that I can see. (Fluke 12)
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iankellogg
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« Reply #18 on: April 26, 2014, 04:17:18 pm »

TESTING DIODES
1. Insert the test leads in the jacks.
2. Put the slide-switch in the continuity/ohms position. The meter selects either the
continuity/diode (R G) or ohms (e) function.
If ohms is selected, press [g] to toggle to the continuity/diode function. To toggle
the beeper on or off in continuity/diode test, press [V]. R is displayed when the
beeper is enabled.
3. Touch probes to the diode (Figure 5A). A forward-voltage drop of about 0.6 V
(typical for a silicon diode) causes the meter to beep once.
4. Reverse probes (Figure 5B). If the diode is good, OL is displayed. If the diode is
shorted (Figure 5C), the beeper sounds continuously in at least one direction.
If the diode is open, OL is displayed in both directions.

from the manual for the fluke 12
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jasonsmith
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« Reply #19 on: April 26, 2014, 04:29:00 pm »

Okay, I'll try it again Ian, what am I looking for, shorts I guess?
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« Reply #20 on: April 26, 2014, 04:29:29 pm »

http://www.allaboutcircuits.com/vol_3/chpt_4/3.html
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« Reply #21 on: April 26, 2014, 04:31:29 pm »

Cool website, thanks.
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« Reply #22 on: April 26, 2014, 05:14:38 pm »

Well I pulled up the datasheet and checked my pinout and I had it wrong. Retested with both methods, resistance and diode and apparently the transistor is working Sad Guess that's not my problem. I'm getting a forward working voltage of about .696v from the Base+ to the Emitter and Collector. Nothing from Base- to each and nothing from the emitter to collector.
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« Reply #23 on: April 26, 2014, 05:21:05 pm »

Check TR502 and X503 (or D503 i cant read the number)
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« Reply #24 on: April 26, 2014, 05:28:36 pm »

Will do, thanks for all the help man!
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« Reply #25 on: April 26, 2014, 05:46:38 pm »

Check TR502 and X503 (or D503 i cant read the number)

TR502 checks out. Did just the same as other one but checked the datasheet first this time Smiley

X501 and X502 both check out as well, couldn't find a X or D503.

Maybe it just needs the voltage set after the cap kit? I have all the parts but without finding something that is broke I think it'll just smoke again.
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« Reply #26 on: April 26, 2014, 05:50:28 pm »

Well there really isnt much else I can think of off the top of my head. Maybe get the meter ready and lower VR501 as low as possible and work from there. Are the fuses still good too? The part of the circuit we have been checking is the power input stuff.
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« Reply #27 on: April 26, 2014, 06:01:14 pm »

Only seeing one 3a fuse on the main board and it's fine. I've checked all the caps again and again for polarity and soldering, just can't find anything, I wish I could find a screw up to end this.

Maybe the voltage needs to be checked. Just have to figure out where and what it needs to be as I'll only have seconds to pull it off, back to the manual. 
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« Reply #28 on: April 26, 2014, 06:02:55 pm »

It may be time to post on klov, buffet will surely know the answer.
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« Reply #29 on: April 26, 2014, 09:43:31 pm »

It may be time to post on klov, buffet will surely know the answer.

Buffett doesn't work on 4600s. I rebuilt two, in both cases I just capped and reflowed them and they work great.
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