Is here anybody with experience on a CHI-2130?
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The US term is GFI, Ground Fault Interrupter.That should be on the primary side of the transformer, and not notice leakagecurrent to ground on DC side filter capacitors.
GFCI's trip at 5 mA nominally, so if you have a leakage impedance <44k ohms, (220V)/(5 mA), you'll trip. So, get a multimeter. Unplug the computer. Turn on the power switch. Measure resistance between the hot and the ground on the plug. Anything less that a few 100k ohms is a sign of trouble.
But another possibility the EMI filter on the input power. A 70
nF capacitor has 44k ohms impedance at 50 Hz, so anything larger
could be trouble. I've seen larger capacitors on old equipment
(and gotten a modest shock from one improperly grounded example in
the days before GFCI!). Most multimeters these days can measure
capacitance, so get one that can, and measure. If it's too high,
you'll have to avoid using GFCI or re-engineer the filter.
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-- John Doty j...@noqsi.com
John, the K was written on there by one of us.In the schematics it’s labeled fl1-fl4Filter line ?
Ah, i wanted to remove the Filters and try some reforming but removing them means complete disassembly of the AC cage and currently its SUPER HOT here. I have a big input filter of an old frequency converter that may be used, too.It is discrete built with inductors and capacitors and most importantly rated to 3.5kW.
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Hey John,i know, but -there is a measured capacity to the chassis of the metal cups. is there any logic reason why if there was only an inductor - and further - there should not be any reason why the GFCI triggers when those are in place.Please correct me if i am wrong, am here to learn :)isnt it at all possible that the machine was built without GFCI in mind, pretty sure there were none at the time, so having that capacity to chassis ground was not a problem at all by 1966 standards.
Sorry for all the noise from me.I have been digging a bit - what is missing is a signal from SAC EPO Interlock / J3 (see schematic)Anybody has a clue what this could be? Would need to dig through the machine where this goes, could this possibly be "Emergency Power Off" and a hidden switch somewhere.Not that there is a keylock somewhere i have not found. Will post back as soon as i get back to the machine again.
Scanning our Documents is coming along. I modified the CHI with a modded version of Carl Claunchs 1130 Loader to easily load the Diagnostic Cards into it.
The CPU has at least 1 problem, this will make it easier to switch between software for debugging.