Birthday Present! Denon DP-1200
- Thread starter fizzgig
- Start date
Pio1980
AK Member
I always go one higher for shunt regulator zeners like this.
Pio1980
AK Member
Hmmmm---, did you say the strobe was lit when it was together and powered up?
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Pio1980
AK Member
We are next going to look at C18 and C19, replace them if you suspect they are getting warm. R19 & R23 will also get hot if C18 is a problem. I can't see anything else right now that could load that line enuff to heat those resistors and not get hot enuff to attract attention other than that zener. Go over both boards looking for components that look like they've been hot.
fizzgig
Well-Known Member
Had to start paying attention to the Lenco as I got a new tonearm in. Will probably pick this back up tomorrow.
My multimeter doesn't have a setting for testing capacitors. What model multimeter do you recommend (at a decent price/features ratio) I get for this functionality?
None of the capacitors get hot, nor do any components on the board look burnt out. But that was with a good bare eye look over. I'll pull out the magnifying glass tomorrow and give it a deep dive in the morning.
My multimeter doesn't have a setting for testing capacitors. What model multimeter do you recommend (at a decent price/features ratio) I get for this functionality?
None of the capacitors get hot, nor do any components on the board look burnt out. But that was with a good bare eye look over. I'll pull out the magnifying glass tomorrow and give it a deep dive in the morning.
fizzgig
Well-Known Member
Agreed, I'm gonna buy myself a cap tester. But until then a buddy brought over his meter. We pulled all caps of the PCB and it seems there are a couple caps out of tolerance.
I'm trying to get a parts list together for all the caps on the power PCB, but it seems as though Mouser has some things I need on back order. So I'll have to tweak some things.
One of the metalized is out of tolerance, C25 to be specific.
Is this a proper replacement for it?
http://www.mouser.com/ProductDetail/Vishay/MKP1847520254K2/?qs=Ur9nHeL6P%2b3E/Mf3bZDKTQ==
We also double checked the motor and it seems to be fine. With good readings when grounded to the chassis.
BTW, I'm learning a lot through this, so thanks for stepping in and helping me. Best to start with something simple like this little power issue than with a nice amp.
Pio1980
AK Member
Probably yes. If it is far out the motor will not start and run.
Pio1980
AK Member
Capacitor replacement 101 for general info;
"I've tested the caps and the replacement caps have the same values but are smaller, is that OK?"
Generally, 'modern' capacitors have a more elegant and efficient construction, reducing their volume size. So unless power dissipation for size is a consideration (almost never for el'ytic types) the trade-out is straight-on good. This brings up cap testing, the most important characteristic for el'ytic types is ESR, Effective Series Resistance, and there are testers for that. I use onesuch, an in-circuit ESR tester, for checking elytics as I do a lot of it. The other test is for capacitance (which cannot be done in-circuit) and being able to make both types of testing is useful to verify capacitor cdx. The only got-cha is that such testing doesn't check caps at working voltage where voltage-conditional stress breakdown may occur. For small-scale work on a few pieces outright replacement on all el'ytic caps in a malfunctioning unit or for total restoration is more economical than buying and using cap checkers unless a lot of such diagnostic work is regularly done.
Unstressed film type capacitors seldom spontaneously go wrong, "safety" types however can be stressed and lose capacity as they self-protect from voltage spikes in power circuits.
Sometimes film caps can have problems with the lead connection inside the package and then need replacing, these can be difficult to diagnose if intermittent. Wholesale replacement of film caps is usually unnecessary unless they are of a type known to be unreliable.
Oil/paper capacitors, which may be encountered in pre-1965-ish gear, are never used in modern era solid-state electronics. Non-hermetically sealed o/p types in waxed fiber or Bakelite casings are generally considered totally unreliable.
"I've tested the caps and the replacement caps have the same values but are smaller, is that OK?"
Generally, 'modern' capacitors have a more elegant and efficient construction, reducing their volume size. So unless power dissipation for size is a consideration (almost never for el'ytic types) the trade-out is straight-on good. This brings up cap testing, the most important characteristic for el'ytic types is ESR, Effective Series Resistance, and there are testers for that. I use onesuch, an in-circuit ESR tester, for checking elytics as I do a lot of it. The other test is for capacitance (which cannot be done in-circuit) and being able to make both types of testing is useful to verify capacitor cdx. The only got-cha is that such testing doesn't check caps at working voltage where voltage-conditional stress breakdown may occur. For small-scale work on a few pieces outright replacement on all el'ytic caps in a malfunctioning unit or for total restoration is more economical than buying and using cap checkers unless a lot of such diagnostic work is regularly done.
Unstressed film type capacitors seldom spontaneously go wrong, "safety" types however can be stressed and lose capacity as they self-protect from voltage spikes in power circuits.
Sometimes film caps can have problems with the lead connection inside the package and then need replacing, these can be difficult to diagnose if intermittent. Wholesale replacement of film caps is usually unnecessary unless they are of a type known to be unreliable.
Oil/paper capacitors, which may be encountered in pre-1965-ish gear, are never used in modern era solid-state electronics. Non-hermetically sealed o/p types in waxed fiber or Bakelite casings are generally considered totally unreliable.
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Pio1980
AK Member
PM sent.
fizzgig
Well-Known Member
My cap tester came in yesterday! This morning I tested all the original caps. Most of them were out of tolerance (high). Tested the new caps and they are within values. Still not sure what to do with these small metalized safety caps. Can I extend the leads and use them, or should I return them and wait until June for the backordered parts at mouser?
See pic attached.
See pic attached.
Attachments
fizzgig
Well-Known Member
You talking about C15/C16 or C2?
Pio1980
AK Member
C20, in series with one of the motor coils, it's the phase shifter that makes the thing turn.