Problem with needle on XA30.5, help!

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Musicfree87

Member
Joined 2016
#1
Hi,

I'm new on the forum. My name is Domenico and I write from Italy.🙂

I recently bought an XA30.5 power amp and I have a question related to the needle on the front panel.

Infact I noticed a strange behavior of the needle:

it is almost always positioned on the left side and it does not move (or move just a little bit) when playing music at a very high level.

I know the needle is supposed to move in case of transition from class A to class AB.

The strangest thing is that the needle moves if I hit with my hand the top panel of the amplifier.:scratch1:
(I made a video clip about this, I will try to share it if I understand how to do it! 😛)

Is the behavior of the needle of my amp normal? Or there is a problem with it?

Anyone experienced similar issues or has an idea which could be the root cause?

Thank you in advance for your help!🙂

kind regards
Domenico
 
#2
open upper lid of case and observe is there some spider activity around needle mechanism

if yes , try to remove it

you can also use gentle breeze of air

regarding amp's general condition/setting - read this, for general info about PL amps setting : Pass Labs X150.5 , checking/adjusting offsets ,Iq and gain | Zen Mod Blog

what's temperature of heatsinks and are left/right side temperatures the same ?

NB that needle movement isn't great in amount ; it;s static as long amp is in A class domain , slightly moving when you approach and in AB/B class domain

(video - you must upload it somewhere (youtube ? ) then put link here)
 
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#6
Thank you for your quick feedback! 🙂
I will try to take a look into the amplifier and see if there is any strange thing next to the needle mechanism or some dust.:xfingers:
I'll let you know the result!
About the temperature of heatsinks, last time I checked it seems to be more or less the same on both sides, but I will check again to be sure.:up:
 
#8
Hi,
here update:
the problem seems to be caused by the movement (sliding) of the needle mechanism inside the housing.
A guy from Pass customer service told me that the first version of the needle mechanism used to have this problem (it is not well blocked inside the housing).
The solutions are:
- glueing
- replacement with new version of the mechanism

Anyone heard about this issue before?
 
#10
I am reviving this old thread, since I have similar issue with my 2nd hand Pass XA30.5 that I just bought.
Or to be more precise: needle was stuck at full (it was moving a little bit as music plays), but I moved it a little bit with hand, at least those metal pieces behind the meter (Shared album - Hrvoje Hudo - Google Photos), and the needle is now completely stuck.

I disassembled the whole front plate and pull out the meter, but since I am total noob in electronics, I don't quite know how this motor works, how much to rotate those metals pieces behind and in front of the meter.

Is there any manual on how those meters works, how to adjust it (and clean it), before I send the whole amp to service which would costs a fortune (shipping, new meter, ..., 600-800€ my estimate)?


Btw, I spoke with customer service, they didn't want to share any info on meter model number or "cleaning" instructions, but said I can try to fix it on my own before I replace the whole damn thing.



cheers,
Hudo
 
#11
considering age of amp in case, it's hardly that meter type/article is even relevant now

cleaning instructions - also hardly to believe that there is universal routine


did you checked Rdc of coil ( resistance between two solder lugs?)

if this is "just" mechanical issue , someone skilled enough could figure what's preventing movement - alien particle or unglued component ( metal cylinder/housing)

if you can't find anyone around, last resort is to pack it very carefully ....... send to me, I'll do whatever I can and send back, postage expenses are all yours
 
#12
Zen Mod said:
considering age of amp in case, it's hardly that meter type/article is even relevant now

cleaning instructions - also hardly to believe that there is universal routine


did you checked Rdc of coil ( resistance between two solder lugs?)

if this is "just" mechanical issue , someone skilled enough could figure what's preventing movement - alien particle or unglued component ( metal cylinder/housing)

if you can't find anyone around, last resort is to pack it very carefully ....... send to me, I'll do whatever I can and send back, postage expenses are all yours
Click to expand...


This is useful info I was looking for - Rdc of coil, I can do that - but can you tell me whats the expected resistance?



I still think its just a mechanical issue, since it was working but after transport and my "fixing", it got stuck.


I am still not sure how to rotate those metal things, since looks like its meant to be adjusted or rotated. Is that to set min/max values the needle goes?



Thanks a lot for the offer, maybe I'll do that at the end, but would like to try fixing it locally first (by learning how those meters work, for start)🙂
 
#13
can't say what is expected Rdc - it's of mere importance that you have any , so we know that coil is not broken

can't give you closer details how to check meter , there are too many variations in physical arrangement of these, but someone with slight experience could manage

see here for starters, and you'll grasp it:

Ammeter - Wikipedia

Galvanometer - Wikipedia

let's see can I link your image directly here :
ACtC-3fwVQiCzGZMCE2DVe2jujCVHPXJDrYqD7G8IbvIQ9HTbeS-07Iqw2OB4FIdeVS1CnN5Rugz2F7ZEEaU-38nUaCL37ve7bm_AT8c8XoNKuLVBf7zgLNyXyb8RyvW9yGcKzQLWxWhYUXFgZJ9wQ9YDF4k-Q=w535-h951-no



anyway , goal is to have needle with coil moving freely ( you can use strip of paper to clean space between coil and outer Fe ring - be careful , use narrow strip

then , without power - check if outer ring is moving - in that case glue is broken, so try to rotate it to get needle aligned with 0

if you got that, put blob or two of neoprene glue between Fe ring and plastic case ; you can also use nail polish or even super glue, last one only if you're sure what you're doing
 
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#14
Problems sometimes arise when a particular meter is no longer made, but then
there generally very similar ones available but which have different mounting holes
and such. Hopefully you can find similar meter and do a little machining.
 
#16
oh yes, very helpful remark

if you apply it with bucket, any glue would do the damage

glue goes on outer surface of metal cylinder, to glue it to plastic surround/case - one or two tiny drops ( whatever glue type), enough

coil is inside of metal cylinder
 
#17
That looks like a very high quality meter movement. I’m not sure if this could be an issue in your case but I have seen problems related to static building up on the meter face, which will interfere with the free movement of the meter. This is more of a problem with plastic meter covers vs glass. I have seen meters ruined by people rubbing the plastic face while wearing gloves and creating huge static charges.
 
#19
We have had several meter suppliers over the years. Analog meters are harder to find these days and the suppliers have difficulty with design and delivery.
Asia might be the place to look for something that could be modified easily and inexpensively to try.
 
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