AR88 Restoration project: Some Questions.
 

Dear group members,
Having Completely restored the front panel, Dials, and knobs on my
second AR88D, I am now starting on the receiver circuitry itself. I've
got an AR88LF in full working order too, so this one is a 'when I've
got spare time at work' project, with bits getting done during
lunch-breaks e.t.c. (!).
The Unit has obviously had a bit of water inside the case, causing a
bit of rust on the tank-capacitors near the base of the unit e.t.c.
I have just got round to removing the power transformer and testing
it. All works OK, so I've re-sprayed it, and re-fitted it.
I have a few questions for the group before I can go much further, so
here goes:

My next part for restoration involves the Chokes associated with the
power supply, namely L49 and L50. One of these is on good shape,
whilst the other one has a kind of Bitumen type stuff leaking from the
bottom. Were these units potted in some way, or is this the dreaded
PCB-based oil leaking out? I can re-spray and re-fit these units if
there's no problem, but I want to weed out any hazardous substances.
(My chokes are the completely cylindrical type, not the square ones
which I've seen in some AR88 pictures on the web.)
The metal-contained capacitors at the rear of the unit will obviously
be replaced, although they're not actually leaking.
Another question, therefore, is where do I source some new
high-voltage capacitors?
Going back to the Chokes, the manual doesn't give any indication of
Value, so I'm struggling to source replacements if required!
Right, I think that's all for now. I'll summarise my questions at the
bottom, but first I must ask if there's anything else to look out for
which may be the difference between Repairable AR88, and
Furniture-only AR88 !!
Right, summary of questions then:
1. Are the Chokes L49 and L50 filled with PCB-containing fluid, and is
it black & sticky when it leaks out?
2. Where can I find out the values of these chokes (not in manual),
and where can I source substitute or replacement parts?
3. where can I source some replacement high-voltage capacitors C96,
C97, C98?
I can fabricate a new enclosure, to make the replacements look the
part!

I should mention that I'm aware of the various spares for sale on
ebay, and my eyes are peeled for any relevant parts.


Finally, if anyone wants to restore their dials, I have Bitmaps of the
original dials. The main dial was scanned and touched up with
photo-editing software, while the vernier dial was drawn on the CAD
system at work. I printed these out on glossy paper ,and bonded them
to the original tufnol disks. I can E-mail these pictures, post them
on CD, or print them out on relevant paper if anyone would like to
update their dials. OK, it's not the best way of doing it, but it's
the best I could do without spending a lot of money, and they'll look
superb for at least 10 years!

Feel free to E-mail me regarding any AR88 info.
Many thanks for reading.
Joe Landy.
Peterborough.
UK.
joelandyman at postmaster.co.uk

If black and sticky, probably tar (or similar) oozing from
the sealed chokes. PCB, IIRC, is a clear liquid, and I doubt it was
in common useage back in WWII era boatanchors.

Pete

"joe landy" wrote in message

Thanks Uncle peter, that's encouraging news. I'm told the three large
capacitors which are sealed in a single case may contain PCB, but it's not a
problem to substitute them. I'm still undecided as to what to do with the
set really. I may look out for a tatty model which works, and swap my
restored front panel, dials, e.t.c onto it. Otherwise, I may completely
strip the guts out, and re-plate the chassis and really go to town on the
restoration. I'm in the right industry for getting plating done as 'a
favour' e.t.c, so it might be the way to go. I'd have to find someone to
re-align it for me when re-built though, as I have no access to a sweep
generator.
Any offers anyone? !!
Cheers for now.
Joe landy
Peterborough
Please reply to joelandyman at postmaster.co.uk if E-mailing directly.


" Uncle Peter" wrote in message
news:FAnuc.15032$6X.7219@lakeread03...
If black and sticky, probably tar (or similar) oozing from
the sealed chokes. PCB, IIRC, is a clear liquid, and I doubt it was
in common useage back in WWII era boatanchors.

Pete

"joe landy" wrote in message

On Sun, 30 May 2004 12:03:31 -0400, " Uncle Peter"
wrote:

If black and sticky, probably tar (or similar) oozing from
the sealed chokes. PCB, IIRC, is a clear liquid, and I doubt it was
in common useage back in WWII era boatanchors.

Pete

"joe landy" wrote in message


Yep, the black goo is tar and unless the choke is running WAY hot I'd
not bother awlfully much about replacing it. As far as PCBs in your
dinsaur not moch to worry about UNLESS caps were replaced any time
from the mid-50s to say the early 90s. My thoughts on units
containing PCBs , asbestos etc; are as follows: Unless there is an
obvious problem (PCBs leaking from caps or loose asbestos powder etc;
) leave the stuff alone. There are many MUCH more hazzardous
substances that we all are exposed to on a daily basis.

Just my thoughts.

Kevin (88LF owner for 27 years)

On Sun, 30 May 2004 12:03:31 -0400, " Uncle Peter"
wrote:

If black and sticky, probably tar (or similar) oozing from
the sealed chokes. PCB, IIRC, is a clear liquid, and I doubt it was
in common useage back in WWII era boatanchors.

Pete

"joe landy" wrote in message


Yep, the black goo is tar and unless the choke is running WAY hot I'd
not bother awlfully much about replacing it. As far as PCBs in your
dinsaur not moch to worry about UNLESS caps were replaced any time
from the mid-50s to say the early 90s. My thoughts on units
containing PCBs , asbestos etc; are as follows: Unless there is an
obvious problem (PCBs leaking from caps or loose asbestos powder etc;
) leave the stuff alone. There are many MUCH more hazzardous
substances that we all are exposed to on a daily basis.

Just my thoughts.

Kevin (88LF owner for 27 years)

In article ,
K-tron wrote:
On Sun, 30 May 2004 12:03:31 -0400, " Uncle Peter"
wrote:

If black and sticky, probably tar (or similar) oozing from
the sealed chokes. PCB, IIRC, is a clear liquid, and I doubt it was
in common useage back in WWII era boatanchors.

Yep, the black goo is tar and unless the choke is running WAY hot I'd
not bother awlfully much about replacing it.

Note that naptha (paint thinner, NOT paint remover) will do a nice job
of removing leaked tar from chassis with a little elbow grease.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article ,
K-tron wrote:
On Sun, 30 May 2004 12:03:31 -0400, " Uncle Peter"
wrote:

If black and sticky, probably tar (or similar) oozing from
the sealed chokes. PCB, IIRC, is a clear liquid, and I doubt it was
in common useage back in WWII era boatanchors.

Yep, the black goo is tar and unless the choke is running WAY hot I'd
not bother awlfully much about replacing it.

Note that naptha (paint thinner, NOT paint remover) will do a nice job
of removing leaked tar from chassis with a little elbow grease.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."