DECmate III and Rainbow 100+

From: Geoff Reed <geoffr_at_zipcon.net>
Date: Thu Feb 24 11:38:41 2005

At 07:39 AM 2/24/2005, you wrote:
>Geoff Reed wrote:
>
>>
>>> > And yes, the whole thing is powered, rather poorly, from 12 volts.
>>> > (Poorly: if you flip significant quantities of white pixels on and
>>>
>>>I've never had this problem. Are you sure you've not got some dried-up
>>>capacitors somewhere?
>>>
>>> > off, the scan area expands and shrinks very noticeably. So clearly
>>> > the supply regulation is seriously inadequate.)
>>
>>
>>the VR 201 monitors have a couple of points of failure, the most common
>>is a coil (IIRC) in the vertical that is potted in wax, they potted this
>>-before- soldering, and wax tended to get down into the solder joint
>>making a bad joint that fails after a while, there is a resistor right by
>>it that also burns up at about the same time.
>Are you talking about the flyback transformer, and the 0-ohm resistor?

nope, not the flyback, I can't remember the part exactly. it is about 1/2
inch wide, 1 1/4 inch long and potted in wax :(


>DEC never seemed to use decent flybacks, as that was the most common
>failure I saw in VT220's, VT320's. The flyback would short out, heat up
>causing the ceramic casing to crack and ooze goo, and take out a
>transistor for good measure. I used to fix these, until the transformer
>started costing more than a replacement terminal did.
>
Received on Thu Feb 24 2005 - 11:38:41 GMT