On Thursday, November 9, 2017 at 3:19:06 PM UTC-5, David Farber wrote:
wrote:
On Wednesday, November 8, 2017 at 7:45:11 PM UTC-5, Phil Allison
wrote:
David Farber wrote:

-------------------


** Good servicing practice requires that you FIRST observe a fault
before delving inside to find the cause.

Consider that the unit may have no fault at all, the reported
noises being fed in from an external device and / or are due to AC
supply transients.


.... Phil


I would agree with you up until the point where after several days
of waiting, and no faults are exhibited, then a peek inside the
unit might give you a clue. Maybe something spilled inside, or
perhaps another tech might have done some creative repairs.


** The flaw with that idea is that you will very often find
something odd looking and wrongly assume it must be the cause of the
reported fault - when it is not.

False alarm reports are VERY common with guitar amps and accessories
plus also with disco equipment and PA gear.

If after a reasonable time running and testing a unit, it shows no
sign of the reported fault then it becomes the owner's problem to
DEMONSTRATE the fault to the repairer.





.... Phil

The difference is: An amp in service is loaded, unloaded, lifted,
carried, vibrated, kicked, and otherwise physically abused.

An amp in the shop sits quietly on a bench or on a shelf with nothing
to disturb it.

A customer who puts equipment into the hands of a tech - and is
thereby spending money has no reason to create a false (and possibly
costly) alarm. An Honest Tech is obligated to take the customer at
their word. Hence the advice to check for visible defects, to tap the
parts with a diddle-stick or similar - in other words, go looking for
trouble. Further, and Honest Tech who has been around a while will
kinda-sorta have a good idea where to start based on historical
experience. And an Honest Tech, when confronted with obvious 'not
right' things will correct them - within the minimum charge limit at
the very least.

Peter Wieck
Melrose Park, PA

Hi Peter,

I am doing this as charity work for a local Jazz group. I occasionally play
with the group at their Vets' Hall in Pismo Beach, CA. http://pismojazz.com/
I know the people there very well and the person that gave me the amp to fix
told me how it failed during a concert last month. As was previously stated,
the problem could be external to the amp. When I continue testing it today,
I'll include lots of tapping and prodding to see if anything unusual occurs.

By the way, are you able to identify this "extra" part that I found inside
the box?

View 1
http://webpages.charter.net/mrfixite...y-object-a.jpg

View 2
http://webpages.charter.net/mrfixite...y-object-b.jpg

Thanks for your reply.
--
David Farber
Los Osos, CA

Make sure that you clean the 1/4 inch jacks as well. I have seen poor connections here cause noise.

Dan