Anyone have a picture of the bottom of a blue HV and the
appropriate locations to check for +-24v and +-30v? The
Amplifone FAQ shows the later green version and it's traces are
different than my blue. I guessed on a few locations and got
-31v, 28.8v and 0. I want to make sure I'm testing the correct
points. If it helps, I can take a picture of my blue to send to
someone to mark-up.
As a side-note, my blue does have the large, brown (ugly)
looking cap at C8. However, I do have a later green HV (also
dead with a red HVT) and it has a newer rectangular style of
cap at C8? Is one better than the other, odds of the later
design still being alive, compatible with the blue design, etc.?
Scott
Christopher X. Candreva wrote:
>On Fri, 16 Sep 2005, Scott Caldwell wrote:
>
>
>
>>My Star Wars (amplifone) recently died and after doing the
>>initial checks, the HV unit is to blame (no neck glow, but
>>loads of deflection chatter - verified w/two working deflection
>>PCBs). Based on the FAQ and my personal observations, I
>>believe I should just shot-gun the HV unit with the following
>>parts, since I don't know how many of these two replaced
>>4-5 years ago when the HV unit was revived). My question is,
>>
>>
>
>To answer the simple part of your question, Mouser or Digikey, whoever gives
>the better price on the order you are making.
>
>However, if it was rebuilt a few years ago already I don't think
>shotgunning is the way to go. This will generally lead to frustration.
>
>One part not yet in the FAQ that does go is C8, see symptoms here:
>http://www.vectorlist.org/Vectorlist/2003/04/0064.html
>
>
>
>>* Note: The caps were replaced on the HV unit about 4-5 years
>>ago and none appear to be bad now, so should I replace them
>>anyway, just to be done with it (I'm on the fence about it)? I
>>
>>
>
>I wouldn't.
>
>
>
>>- Q1 (2N3904)
>>- Q2 (MPSU07)
>>- Q3 (BU406D)
>>- Q4 (8239)
>>- Q5 (2N3904),
>>- VR1 (7824CV)
>>- VR2 (7924CV)
>>- 1N4001 (diodes, believe there are two at CR5 and CR6)
>>
>>
>
>>From your list above: Check the 24v regs -- if they are HV they shouldn't
>blow. If +24reg is blown, suspect C8 as mentioned above. While anything is
>possible, I wouldn't bet that any of those things went bad. (As in I padded
>out an order with spares of all those and haven't used them in years).
>
>The BU406D is a fuse. :-) I had to source these separately (from the place
>in the FAQ that is on Long Island, don't know if they still have any) -- and
>buy at least a dozen, or whatever it takes to fill a min order. If ANYTHING
>goes in the Ampliphone you'll blow this.
>
>(Side note -- what would it take to add a fuse to the BU406D path, so the
>damn thing doesn't keep blowing ?)
>
>I've had two ampluphone's fail years after a rebuild, and both times it was
>C8.
>
>-Chris
>
>==========================================================
>Chris Candreva -- chris@westnet.com -- (914) 967-7816
>WestNet Internet Services of Westchester
>http://www.westnet.com/
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>
>
>
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Received on Mon Sep 19 21:57:23 2005
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