Marantz PM-66KI Signature Amplifier Repair - New Capacitors, Transistors, Dry Solder joints and more
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- Опубліковано 7 вер 2024
- Another eBay bargain for spares and repair, investigating faults and fixing issues with a Marantz PM-66KI Signature Edition. and a nice walk around the unit and its features.
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The stuff on the board by the main filter caps is glue thats become corrosive, not leakage. Hard to believe you don't know that.
You know, I'd also bet those caps might not even test half bad being 12000uF
Totally agree with you! Thank god I can repair my Hi Fi gear, because we have so many few and poor engineers!
This main board would have me looking to buy and ultrasonic cleaner.
I do have one, but to be honest even though I've looked at it a few times, I've never been -that- interested to clean it up.
Just fixed a 66 SE that was popping fuses. The dim bulb tester was pulsating indicating that at least one filter cap was being drained. Installed new filter caps. Reflowed all solder joints on the main board as well as all the cable connectors and the phono jack. It's currently on soak test being fed with noise from the phono pre-amp. The only remaining problems being a slightly scratchy volume control and the power switch that I turned into a momentary power switch through manhandling. Pro-tip: don't be fixing things past bed time.
Most def. I have actually recently recapped the phono stage on mine however sadly it does not get a lot of use nowadays!
C801 and C802 which are the filter caps were the correct spec as you received it. There is a addendum for the service manual specifically for the KI that explains the electrical difference between the PM66SE and the KI. Just got my own KI as an upgrade to my PM44SE and you are correct the wires from the filter caps to the transistors are factory. They are in mine which has never had the bottom panel snipped.
Thanks for your insight, that's great news. It seems like such a half job to just fire some wires in! I still have the amp and use it daily. It sounds great.
One thing I would suggest is to deoxit spray the sliding contact switch just above the phono pre amp. It is controlled by the long flat plastic sliding cable, when you select source.
I had to open mine up again last week and give it a clean as the source select would sometimes cause left channel distortion.
If he had done his homework before diving in and "repairing" the amplifier he could have saved time and confusion.
Back in the mists of time we used wave solder machines. Taller components were glued in place to stop them moving. Dangerous and unhealthy standing next to a bath of solder and they had halon fire extinguishers built in.
Sounds crazy!
The Ken Itchywotsits versions are always worth keeping.
Fantastic video, just what I needed, shame there was not a problem with the relays as well
Hi thanks, I can certainly help you with it if you have an issue. There's only really the one - the speaker protection relay.
In my experience they're usually good and if it doesn't click when you turn your amp on its just doing its job and protecting your speakers!
@@pwrestoration Thank you, my questions would take a while to list, but watching your video I noticed the delay before the speaker protection relay operated which mine does not, took relay out and applied volts to coil which operated and contacts seemed ok with continuity, I recently changed the the protection chip, trying to repair for a friend and quite enjoying it but my electronic skills are not that good, the information in your video has explained a few things
@@cjnormin3582 the two contacts on the protection relay that are furthest away from the speaker terminals should have no voltage going to them. If they do it won't open and allow your speakers to work. It's blocking that voltage to save your speakers. Measure the DC current between the two
@@pwrestoration there is 19v across the coil
I was thinking the coil operated in a safe condition not the reverse, thank you
Nice work...cheers.
Safety lamp fitted 40 watt ? Glowed bright red then went out so hopefully no shorts, will carry out the further checks you recommended after reflowing all the dry joints which there are a lot of, bought a pair of magnifying glasses and can see more clearly the joints, I am surprised at the quality of the soldering
Hi sir ,nice ,next repair amplifier 😉
Thanks for this video. I have a Marantz PM52se amplifier and having problems with it. Sometimes the speaker relay does not click and when I press the speaker select button (set 1 or 2) it sometimes clicks and I get music but then there is loid popping and clicking coming through the speakers so I have to turn the amp off to avoid any damage to the speakers. I cannot afford to get it repaired so was thinking of having a go myself but not sure where to start.
Loud popping indicates you have DC current going direct to your speakers. Don't plug them in anymore, you'll fry them.
The relay sometimes clicking will be due to the voltage to the speakers fluctuating depending on the fault. There should be hardly any voltage out if your speaker ports.. if you have a multimeter test across each pair of terminals on the back. The relay must have clicked for this to work though.
Otherwise it sounds like you have a similar fault to what I had, a shorted component on the board which is making your speaker outputs live with probably DC voltage.
@@pwrestoration Thanks so much for your reply it is much appreciated. what would be the best way to track down the shorted component? I will test the speaker outputs with a multimeter if I can get the relay to click first.
@@Chaggy1978 it's not an easy task but this is what I'm doing in this video, testing components for shorts. I'd check all your larger transistors first, then the smaller ones. Get a service manual and test for voltages on the power board. Don't forget it's DC on the power board, set your multimeter to it.
For testing the transistors you're better off pulling them off the board and using it in diode mode
@@pwrestoration Thanks for the advice again I am very grateful to you. The amplifier relay will no longer click on now so I think it's time to test the transistors as you said. If one of the main larger transistors has failed, is it just a straight replacement or does the bias need adjusting also? Thanks
@@Chaggy1978 if it's not clicking that means that the speaker output lines are now powered. The relay is a protection feature to stop excess voltage getting to your speakers, so it's doing a great job!
The transistors generally come in matched pairs as new for about £6. I'm not saying that's deffo what it is, but in my experience most of the time they fail. A good solid visual check helps too, look at all resistors and components and look for chatting it burning.
The two large capacitors on the power board (the big board in the middle) generally could also be a culrit. Again £10 for a pair to replace them.
Last thing is definitely visually check all solder connections under that power board. The smaller Transistors get hot, and as such over time cause dry solder connections.
I cannot watch this no more!
That's a double negative and infers the positive! 😅
Funny how some folk feel the need to make some shitty comment rather than, y'know, just turning off the video and finding something else to watch. So strange.
that dark matter is corroded glue not capacitor leakage
Yep, I realised that after the time 😄
I have the Marantz pm66se ki signature as in this video. I'm having an issue that the amp will no longer turn on. I thought the first thing I could do is to check the fuses. I opened the top, replaced the wall plug fuse with 5 amp replacement. I swithed it on and the red light came on. A few seconds later there was a spark inside and it blew the plug fuse I assume but the fuse near the relay inside looks alright. I'm far from an expert but wondering if some of my components have gone. What do you think is wrong ? and where shall I start for repairing safely and correctly. I know capacitors can be dangerous so I won't be rushing in to fixing until I learn everything I need.
Sounds like you have a hard short to ground.
It will either be one of the large six transistors on the outside of the power board, dry solder joints, or the smaller transistors next to the DC rectifier (the plastic square thing that looks like a stool).
Look for burnt marks or discolouration around those.
After all that check the big two main filter caps
If you're in the UK and want to sell it give me a shout though!
I used to have similar issues with my PM66, if you have cold solder joints at the middle, small power transistor, it generates so high off set to the power transistors, that through the main transformator the current increases 10x as the iddel current of 220V. Therefore the main fuse can be blown. It was a fundamental mistake the You used 5A fuse,corresponding 1200W , at this current the transistor can be blowned too. My advice look for the cold solder joints att the main transistors.
sorry but, 30 min in and it's almost scary how little you know about amplifiers electrically
Ah I knew absolutely nothing when I started the PM40 repair. This one, a little more, but enough was understood to repair both. This PM66 has since been my main amp and is working fine, so I mean, does it scare you that you don't need to know much in order to make a successful repair?
@@pwrestorationI’m in the field myself and see more and more amplifiers destroyed by people who randomly start recapping amplifiers because “caps dry out”. They can’t do a proper solder job and ruin traces removing the old caps.
Perfect fine caps like your Elna 12000μF examples are thrown away because the Chinese all in one tester said the capacitance decreased or the ESR is to high. In fact the capacity didn’t change much but the measure at a higher frequencies (most of the time 3000 or 10000Hz for Chinese testers) than the caps would ever run on. (100 or 120 Hertz depending on your countries energy distribution net) If you search for the original data sheet you see all those caps original were measured at 100 or 120Hz
And that is just one of many pitfalls people walk in to.
That is not capacitor leakage its glue. Glue is a standard and is used to stop vibration and many caps are glued in at factory. Those filter caps would probably be fine. You make several statements and assumptions there are not correct. You didn't measure or adjust the bias either. I think you need some more electronics knowledge before carrying out any more "repairs"
This was a fair while ago now Mike, a lots changed. But you're right. However that said, I fixed it. I later adjusted the bias and also did a heap of upgrades etc as time progressed.