"Model 688" universal chassis manual/schematic

ieure

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"Model 688" universal chassis manual/schematic

Anyone have any info on this chassis?

fAWmRvU.jpg


I don't see a manufacturer. Says "Model 688" on it, and I see it for sale a couple places. I picked up a game with one in it and I'm having a couple issues I want to see if I can work out.
 
8 Liners chassis

Are you within the spec's posted
on the heat sink label for the yoke?

Even though the ac plug plugs in either way
the is a certain way you need to plug it in
and can cause it to not start up.

It is a hot chassis and needs a isolation transformer.
While you waiting for service manual..what kind of problem are you having
with it?
 
Are you within the spec's posted
on the heat sink label for the yoke?

Even though the ac plug plugs in either way
the is a certain way you need to plug it in
and can cause it to not start up.

It is a hot chassis and needs a isolation transformer.
While you waiting for service manual..what kind of problem are you having
with it?

Two issues, first is that the image is too wide, likely because this is an oddball 18" tube (yes, 18", not 19") and the chassis says for 20"/21" tubes. But I was hoping there was some way to make it smaller like on a K7000.

Second is that the image has some dimming issues which are hard to explain. Basically, the brighter the image it draws, the more the overall brightness decreases. So if I adjust so a bright screen looks correct, a mostly dark screen has a very bright black level. If I adjust so a mostly dark screen looks correct, a mostly bright screen is too dim.

The individual screens look fine. But it can't be adjusted such that it looks good across the full range of brightness.
 
???????????????

Two issues, first is that the image is too wide, likely because this is an oddball 18" tube (yes, 18", not 19") and the chassis says for 20"/21" tubes. But I was hoping there was some way to make it smaller like on a K7000.

Second is that the image has some dimming issues which are hard to explain. Basically, the brighter the image it draws, the more the overall brightness decreases. So if I adjust so a bright screen looks correct, a mostly dark screen has a very bright black level. If I adjust so a mostly dark screen looks correct, a mostly bright screen is too dim.

The individual screens look fine. But it can't be adjusted such that it looks good across the full range of brightness.

You may need to hook it up to a 20/21 inch tube
to test the chassis first before you try to modify it...
Some of the symptoms can be related to the wrong yoke..


Are you within the spec's posted
on the heat sink label for the yoke?

What is the B+ set at???

what is the Horizontal ohm's of the yoke being used????

zero your meter ohms then measure the horizontal winding of the yoke

by pushing your meter probes up the female connector disconnected

from chassis..
 
There should be a width range selection jumper wire. Look over by those orange/brownish capacitors at that red wire with the what looks like a black push on single pin connector on it. There should be two posts the jumper wire can plug on to. One should be labeled (N)arrower and the other should be labeled (W)ider. Only move these jumpers with the power off.

In general, the "universal" chassis sold at 8liners.com and Alva Amusement are either Jen Shinn or Wei-ya (a.k.a. Huai Electronics) brand.
 
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