MicroVAX II Console Garbling Characters
elson at pico-systems.com
Wed Aug 24 10:51:48 CDT 2016
On 08/24/2016 09:53 AM, Jerry Weiss wrote:
>> On Aug 24, 2016, at 9:41 AM, Rob Jarratt <robert.jarratt at ntlworld.com> wrote:
>> I have a MicroVAX II which has started garbling and losing characters output
>> to the console. It had seemed that re-seating the processor board would fix
>> it, but that no longer seems to be the case.
>> I was just wondering if anyone else has ever come across this failure mode?
> I’ve seen similar with under two occasions.
> 1) Non-compliant USB adaptor - Doesn’t fully support RS232C levels
> 2) Poor grounding, noise in the data lines - long cable runs or devices on different sides of the (US) power main.
> I have not dealt with component problems on the KA630 itself.
The console interface is a set of 9636, 9643 and 9639 chips
(8-pin DIP). I had mine blown out about 1988 or so when a
power supply failed. There are a couple capacitors and
resistors related to that circuitry, too.
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