Marantz 2270 Slow to Click in...sometimes

[6taafondo]

Ah ok, thank you for the information!
.. and know whether or not the adjustments I make are still within acceptable ranges?

To know whether or not the adjustment is within acceptable range, you need to judge heatsink temperature and how much power you're wasting through bias. Both things together with output devices type and the equipment's power capability would tell you if you're pushing bias unreasonably high. Where you have set it now is safe enough.

 

[OMGCat!]

I'd add that picking up one of those laser temp guns from Harbor Freight or someplace similar might make it easier to check.
I swore I had a channel that was hotter in an amp I was restoring but the gun showed them to be nearly identical.
It's also useful for other things like playing with your cat.

 

[grailseeker]

Thank you, thank you!
I have read the bit about dynamic biasing in the service manual. Can/should I depend on that functionality?

I'd add that picking up one of those laser temp guns from Harbor Freight or someplace similar might make it easier to check.
I swore I had a channel that was hotter in an amp I was restoring but the gun showed them to be nearly identical.
It's also useful for other things like playing with your cat.

In fact, I took that very measurement for both sides (with a Harbor Freight temp gun, no less!) on the heat sinks just before closing it back up and they were almost identical, but, yeah, now I could swear one side is warmer; less so the longer it's in use, but still noticeable.

alas, I have no cat! haha!

 

[6taafondo]

I have read the bit about dynamic biasing in the service manual. Can/should I depend on that functionality?

Of course! Many good amplifiers have temperature bias compensation, not just this Marantz.

If you need to make a slight bias correction just be SLOW. Let temperature settle down to the new value. Bias will tend to vary slightly as temp changes. This is why you need to give the thing time.

 

[jjsxr9]

Hello,

I'm running into the same issue with my 2270's relay; it takes about an hour for it to kick in anymore. This thread has been pretty helpful in identifying the problem but I'm not sure what to do next....

Serial # 451134 Mfg date: 8/27/76
I have attached pictures of the P800 board, it appears something has leaked and there is some corrosion. Specifically on R806 and H802 I believe. If I were to guess I would say that C803 leaked.

Any advice is much appreciated.

Thanks!