I purchased Yamaha P2200 power amp. I already own P2201 (same app minus the VU meters). The P2200 was missing both needles on VU meters, light bulbs are out but the amp is functional. Measured the output and read 23.5mV and 26.7mV on each channel. Not bad.
I started cleaning the amp. Similar to P2201 I have it is has seen a better days. Some previous owner scratched his name and phone number on the bottom and back plates. Perhaps I should call him once a day...
Once I removed the VU meter plate, I noticed that needles on both VU meters are broken. I removed VU meters and discovered the needles. What would be the best way to glue/secure them?
The VU meter on the left side is working but the one on the right side doesn't. Also the bulbs get no power. I have read that cold solder could be the problem with these amps, something to check...
Any advice on repairing the needles is welcomed. I thought of using superglue with baking soda, epoxy, solder (probably bad idea as the insulation on the needle is likely to get damaged once heated), shrink tubing (won't last and needle could be too close to back plate)... I unerstand the added weight likely to affect meters accuracy.
I started cleaning the amp. Similar to P2201 I have it is has seen a better days. Some previous owner scratched his name and phone number on the bottom and back plates. Perhaps I should call him once a day...
Once I removed the VU meter plate, I noticed that needles on both VU meters are broken. I removed VU meters and discovered the needles. What would be the best way to glue/secure them?
The VU meter on the left side is working but the one on the right side doesn't. Also the bulbs get no power. I have read that cold solder could be the problem with these amps, something to check...
Any advice on repairing the needles is welcomed. I thought of using superglue with baking soda, epoxy, solder (probably bad idea as the insulation on the needle is likely to get damaged once heated), shrink tubing (won't last and needle could be too close to back plate)... I unerstand the added weight likely to affect meters accuracy.
i'm fond of the P2200 myself and loved the metering but if they are damaged it's tragic. short of cannibalizing an old chassis for working meters they are impossible source.
would you consider an led meter module?
would you consider an led meter module?
I have no idea how LED module would look like. How much something like that would run? I wanted to try repairing the existing VU meters. LED board doesn't get power. I may try look into this tomorrow.
a VU meter is a delicate mechanical device and when they've been hit with enough signal to slam the needles against the stop peg at the end of their travel to break them the return springs get stretched or the drive coils go open so go ahead fix the ones you have and cross your fingers they'll work properly, in the past i've tried and failed but who knows you may get lucky!
here take look at this
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thank you for the reply and sharing the pictures of LED meters. I resoldered all joints on the meter board, but it made no difference. Bulbs are still not getting power and right meter not moving at all. All diodes on the board appear to be OK. I checked to make sure the needle is not stuck on the right channel. It doesn't move when I run diode check with my DMM like the left channel meter does. Left one measured 0.82kOm and the right one 3.8kOhm. At this point I will just use the amp as is.
LEDs VU meters not my cup of tea. But they can be quite interesting depending on the application.
LEDs VU meters not my cup of tea. But they can be quite interesting depending on the application.
From what I think you described, the meter needles have literally snapped off or simply become detached from their armature. Close inspection with a loupe or good mag. lamp should reveal how they were actually attached and I do think you need to know how, in order to plan a repair of something as delicate as a sensitive moving coil meter. I would be looking for the help of an instrument maker or watch repairer. These guys are scarce now but I have had some great help and suggestions from a local watchmaker that have solved similar problems in the past.
We don't know what Yamaha's engineers or the meter manufacturers were thinking about the amplifier's longevity at the time, but it seems they didn't anticipate a need to stretch the service life to 50 years or more, as may be the case here.
We don't know what Yamaha's engineers or the meter manufacturers were thinking about the amplifier's longevity at the time, but it seems they didn't anticipate a need to stretch the service life to 50 years or more, as may be the case here.
Thank you Ian. I checked the user serviceable fuses and found 6 some amps fuses there instead of 7A. Most likely it had a short and the meters failed as the result. I agree finding a watch repair person is likely the highest chance of fixing the meter. I am using the amp in the quest bedroom right now until I figure out how it can be bridged so that I can try it in my main listening room. At this point I am likely going to give up on the meters unless I can find a replacement at low cost. Found one on reverb but it is >$100 for 1 meter shipped. One of them is working but it makes no sense in spending any effort fixing light and re-attaching needle to the working meter since I won't be able to repair the second meter on my own.
be careful what impedance load you put on the P2200 in bridge mode, anything less then 8 ohms is risky!!
Thanks for the warning. I read it has overcurent protection set to 2.7Ohms or something like this, so in bridge mode that would be 5.4 Ohms. But most speakers have impedance changing a lot across the audio band, so one has to measure it or find the measurements done by someone else. Frankly I am not sure if bridged mode is going to buy me anything. The amp already has tons of power in its reserves(not as much as parasound jc1 but still). Bridge mode will drop the damping factor by 2x, distortions would rise, but this is all theory. Just curious what would happen in practise.
some times there is a tiny screw holding the needle to the armature. It could be slightly overtightened and cause the needle not to move. It could also just need a drop or 2 of oil on the pivots. If the spring is broken you are out of luck. You could try gluing a small wire on the back of the needle across the break. Dont worry about accuracy they are for decoration only. The needles will never move fast enough to keep up with the music and will always be a few db's off. If you can OHM the meter coil with a 20K or 50K resistor in series with the VU meter to see if the meter coil is open or not. My wife took a mantle clock repair course many years ago and fixed her grandfather's mantel clock 1930's vintage. If she can fix her clock you should be able to as well. Yes the clock still works.
sometimes the bulbs are all in series if one is open you wont read any voltage across a single bulb.
Hello i fixed many of many of these in fact i am working a couple right now
the lamps .. there must be a break in the pcb the traces are getting brittle so they crack perhaps someone was trying to replace the bulbs and cracked it. did you check the bulbs ?
also there is a unrepairable Analogue brain on these boards that is as Turk say impossible to fix so before you fix the meters try to buy a cheap set on ebay to see if the unit is working at all and even if you hook up your broken meters and see movement it might be sporadic movement and
unusable .. i have this on one now but depending on its condition .. it might be worth buying a working amp beat up unit and take the parts from that and if you plan on keeping it spare parts are very hard to find but you can also sell the working channels and parts probably for more than you purchased it for.. good luck
the lamps .. there must be a break in the pcb the traces are getting brittle so they crack perhaps someone was trying to replace the bulbs and cracked it. did you check the bulbs ?
also there is a unrepairable Analogue brain on these boards that is as Turk say impossible to fix so before you fix the meters try to buy a cheap set on ebay to see if the unit is working at all and even if you hook up your broken meters and see movement it might be sporadic movement and
unusable .. i have this on one now but depending on its condition .. it might be worth buying a working amp beat up unit and take the parts from that and if you plan on keeping it spare parts are very hard to find but you can also sell the working channels and parts probably for more than you purchased it for.. good luck
Thank you for suggestions. The voltage rail that provides power for the bulbs was down. I don't recall if I checked the bulbs or not. It is possible that the traces are broken like you said. If I ever run across a broken amp I will buy it, but they are hard to find. For the time being I gave up on the idea of fixing the meters. I installed the amp in the guest bedroom and I cannot even see it from the listening spot so it doesn't bother me that the meters are not functional lol.