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Old 09-29-2020, 08:27 PM   #15
khajr
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Join Date: Sep 2020
City & State: Lexington, KY
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Line Voltage: 120VAC 60Hz
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Posts: 19
Default Re: troubleshooting definitive technology prosub 60

Quote:
Originally Posted by momaka View Post
Measure across the four caps after bridge rectifier D1, if that is more convenient. C1 and C2 are in parallel, so you should see the same voltage across them, and hopefully it should be around 160-170V DC, depending on how much voltage your dim bulb is dropping on the AC. Likewise, C3 and C4 are in parallel and should also have the same voltage across them. Lastly, placing your red (positive) multimeter probe on the positive lead of cap C1/C2 amd the negative (black) multimeter probe on the negative lead of cap C3/C4 should give around 320-340V DC. Alternatively, you can measure the DC voltage across the bridge rectifier (+) and (-) pins. Whichever you chose, just be safe and pick the one where you're not likely to touch any of the metal parts in that area, as those DC voltages are quite high and can be dangerous.
Thanks for the help momaka. I am waiting on new Q1 and Q7 mosfets to come in. Then I will check those voltages. Yeah...I am trying to be very careful. I took Q1 out and pins 2 (drain) and 3 (source) were closed. 1 (gate) and 2 (drain) were open. and 1 (gate) and 3 (source) were open. I am going to take Q7 out and check too.

Last edited by khajr; 09-29-2020 at 08:28 PM..
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