Got a Yamaha M4!!!! But needs work
- Thread starter lha1992
- Start date
Just hooked up a Pioneer CT-F1000 as a pre-amp since it has pre-amp controls and the M4 is now singing ZZtop right now!! Yeah!!
Well I kinda believe it was the old trim pots in there. I really like these new multi-turn Bourns! They really do the job good and getting everything spot on.
Who really knows, the 30 year old caps could have been some of the trouble too you know. I mean this was a really really early M4, date code 10-12-'79 so.
Anyway, I'm really happy! Thanks dude and everyone who helped get this thing running!
Well I kinda believe it was the old trim pots in there. I really like these new multi-turn Bourns! They really do the job good and getting everything spot on.
Who really knows, the 30 year old caps could have been some of the trouble too you know. I mean this was a really really early M4, date code 10-12-'79 so.
Anyway, I'm really happy! Thanks dude and everyone who helped get this thing running!
Will, maybe I should have you breath on my M-2?
Sir.Byrd
Lunatic Member
It was kind of fun, and I didn't even lose any screws (both in my head from the amp)
What's wrong with your M-2?!?
BrianR
Randomly Variable Anomaly
Great to hear that the M4 lives! Pretty great amps, and I'm kinda partial to this series of Yamaha gear since growing up with some of it. Got my dad's old C4 and my brother's M4 sitting on the floor here.
Unfortunately, this M4 is sick too :tears: Don't think it's anything too serious though.
Unfortunately, this M4 is sick too :tears: Don't think it's anything too serious though.
I keep loosing idle bias. Sometimes left, sometimes right, sometimes both. Dave and I have been chasing a few things with mixed results. Thinking about shipping it back to the master himself to check it over...
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The good ole M4 is still running good. Though, whenever I turn it on you see a power jump on the meters. And also, I should give it a good deoxit bath because sometimes the right channel will go out and I have to turn the volume up on the CR-1020 to get it going again. It did the same thing on the Pioneer CT-F1000 that I used as a pre-amp earlier. Other than that, everything is good!
Sir.Byrd
Lunatic Member
If you want to bring it down for a deoxit treatment you are welcome to do so.
Are there level set knobs on the rear of the unit? That could be the culprit.
Power jump at turn on could be normal, do you see it in the speakers too?
Thanks dude, I might bring it down for a deoxit treatment sometime. Yes there are level set knobs for both channels on the back and when it was playing I moved the right channels knob and could hear scratchiness.
The power jump is just seen on the meters. You can't hear it in the speakers cause the speaker selector works the relays and I turn them off.
Be careful what you use on them.The input level controls are single gang-30Kohm-15mm-PC mount with CARBON resistive pads.Very hard to find these and still use the OEM knobs.
aidynphoenix
Super Member
getting even the case for a m-4 is a score for $20. imo..
+1
If I recall, I think I just wind them back and forth 30 times to clean them up. Then set them max and leave them.
BTW, Dave will you put a muzzle on that thing? Gawd he's fugly.
Hey thanks! I couldn't believe myself either when I got it.
I remember what Dave is talking about, he said to not use Deoxit D5 on them but use D100.
I'll put a muzzle on when you get a botox treatment and see a dentist about that overbite.
I use Deoxit D100 - no solvent!
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So I thought i'd give ya'll an update on the M4.
Its still in my main system but i'm still tryin to find a good separte preamp or a C4. Till then, i've been using my CR-1020 but the 1020 needs its power switch rebuilt so the whole system is gonna be going down for awhile.
Other than that, the M4 has been great! Though, I need to deoxit the molex connectors because sometimes I have channel drop out on the right channel. Sound will register on the output indicators but no sound will come out of the right channel and i'll have to give the volume a jump to make it going again. Also, whenever I power the amp up I see the indicators jump and it also does the same on power down. No volume or anything on. Maybe in-rush current? IDK
Anyway, I love this thing! Makes me a Yamaha fan now for sure!
Its still in my main system but i'm still tryin to find a good separte preamp or a C4. Till then, i've been using my CR-1020 but the 1020 needs its power switch rebuilt so the whole system is gonna be going down for awhile.
Other than that, the M4 has been great! Though, I need to deoxit the molex connectors because sometimes I have channel drop out on the right channel. Sound will register on the output indicators but no sound will come out of the right channel and i'll have to give the volume a jump to make it going again. Also, whenever I power the amp up I see the indicators jump and it also does the same on power down. No volume or anything on. Maybe in-rush current? IDK
Anyway, I love this thing! Makes me a Yamaha fan now for sure!
aidynphoenix
Super Member
maybe there is a cold solder connection responsible for your channel drop??
Protect relay contacts.:yes: If you using speaker A then try speaker B or vice-versa.There are two seperate relays.