[sebhc] H90

[Carroll Waddell]

Bill Beech (NJ7P) wrote:

> I am trying to repair an H8 computer.  I have downloaded the manuals, 
> but there is only a schematic for the cassette interface.  I suspect 
> the schematics were part of the larger foldouts for the boards.
>
> Anyone got the schematic scanned in for the CPU, Memory and Disk 
> controller cards?
>
> Thanks!
>
> Bill
>
> Carroll Waddell wrote:
>
>> Lee Hart wrote:
>>
>>> From: Carroll Waddell
>>>  
>>>
>>>> This board is hard to troubleshoot because it's so hard to get
>>>> to in the machine.
>>>>   
>>>
>>>
>>>
>>> Ah, you do not know the secret!
>>>
>>> Tape a piece of nonconducting wood, foam or rubber along the top 
>>> edge of the CRT (to prevent shorts). Install the CPU board 
>>> horizontally, so its lower edge sits on top of this insulator. The 
>>> two screws that normally mount the CPU board still go in the 
>>> vertical brackets.
>>>
>>> You'll find that the cables are barely long enough so with careful 
>>> routing you can still plug them in. Now you can easily get at both 
>>> sides of the board to probe things, change parts, etc.
>>>
>>> -- 
>>> I would not waste my life in friction when it could be turned into 
>>> momentum. -- Frances Willard
>>> -- 
>>> Lee Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>>> -- 
>>> Delivered by the SEBHC Mailing List
>>>
>>>  
>>>
>> Thanks Lee. I'm glad to know to turn the CPU board around. I now have 
>> the CPU board and memory expansion board working. Will try diskette 
>> adapter and serial adapter next week. Thanks again.
>> Carroll
>> -- 
>> Delivered by the SEBHC Mailing List
>>
>>
>
> -- 
> Delivered by the SEBHC Mailing List
>
Bill,
If you don't find your schematics, I'll look next week and see what I 
have.  I just finished repairing an H8 to put on EBAY, so I'm sure I 
have those things lying around somewhere. I'll copy them for you next 
week and mail them to you.
Carroll
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