1 Aug
2014
1 Aug
'14
5:28 p.m.
John,
I've dug through the service manual and it offers the part number, and
voltages, will need to check if the freq. is shown. From what I can tell
from the schematic, the flyback is generating 8KV for
the CRT, 800v for
intensity through a pot on the back of the machine, 12v, and 48v.
There
are at least 2 flavors that HP sourced, I thought I had a replacement found
(it was already sold) with the same part number but looked like a newer
style, totally enclosed, where the one that came with my unit is an open
frame/coil (suitable sealed of course). I did successfully solder back the
broken leads, just had an extra lead that I wasn't sure which where it'd
come from. I think Tony may have pointed me in the right direction on
this, will need to go back and check my work. I trained in the early
eighties as a radio/tv tech then went on to flight instruct and do fire
protection design and sales for the next 25 years, just a little rusty
still. I'll check those folks out and see if they may have a cross
reference to this flyback.
Tom
On Fri, Aug 1, 2014 at 12:42 PM, John Robertson <pinball at telus.net> wrote:
On 07/30/2014 5:30 PM, pdaguytom . wrote:
I've got an HP 85a that didn't fare well
in it's recent travels to me.
The
flyback transformer broke away from the video board breaking 4 of the 6/7
leads (this was apparently an early flyback, it had a U shaped threaded
rod
secured with nuts & washers on the backside of the video board that broke
at the outside bend). The unit did boot and run before it's trip so its
worth repairing. I've not been able to source the transformer (or the
video board) at anything below just buying a complete machine again.
Anyone got a lead on one or know of a transformer that could be
substituted?
Tom
The flyback can probably be substituted if you can figure out the
frequency and
output voltages and match to a similar one. Is the HV diode
separate or integrated into the flyback body? Is the insulation wax or some
other compound?
Depending on the era it is possible that HP used off-the-shelf flyback for
their monitor so if there are manufacturers markings on the flyback that
may give a guide.
There is a TV/Radio parts shop in our area that has(had?) a cross
reference for flybacks and they may be able to help -
http://mainelectronics.com/orderform.html (contact info at bottom of this
page).
I have a collection of NOS Motorola 1970s B&W monitor parts that were used
in arcade games, including a variety of flybacks. However I have no idea if
these are potentially of any use to you...
I've had some success soldering on tiny wires to flybacks where there was
just a smidgen of wire sticking out. A steady hand and a hot tip (to melt
off the varnish) can work wonders. The added wire needs to have flex
available after added so it isn't going to stress the joint if the flyback
body shifts at all.
Good hunting!
John :-#)#
--
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Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
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