Re: Tech : Electrohome G08-003 image too big

Check pin 8 of the HV unit for +100 - +126 VDC...there's a small pcb on the
side of the HV unit, with a small trim pot. Adjust this voltage and see if
you get better results.

----- Original Message -----
From: "Zitt Zitterkopf" <zittware@hotmail.com>
To: <vectorlist@vectorlist.org>
Sent: Wednesday, February 23, 2011 9:21 PM
Subject: Re: VECTOR: Tech : Electrohome G08-003 image too big

>I did find a couple of pins on P900 with bad solder joints.
> I went ahead and touched up all the solder joints on the HV board - adding
> solder if necessary.
>
> Sadly; made no difference.
>
> I tested the transistors on the HV board and seemed to test ok. I'll have
> to
> pull the board again to see if I can find anything else.
>
> -----Original Message-----
> From: Mark Jenison
> Sent: Wednesday, February 23, 2011 12:05 AM
> To: vectorlist@vectorlist.org
> Subject: Re: VECTOR: Tech : Electrohome G08-003 image too big
>
> John,
>
> Yes, low HV will cause the image to be too large (commonly refered to as
> "bloom"). Check the HV section, caps, header pins, trim pots, etc.
>
> ----- Original Message -----
> From: "Zitt Zitterkopf" <zittware@hotmail.com>
> To: <vectorlist@vectorlist.org>
> Sent: Tuesday, February 22, 2011 9:44 PM
> Subject: VECTOR: Tech : Electrohome G08-003 image too big
>
>
>> I’m in the beginning of the process of restoring my Star Trek Captain’s
>> Chair:
>> http://www.austinmodders.com/modules.php?name=Forums&file=viewtopic&t=2724
>>
>> having purchase an untested board set and an untested G08 Electrohome
>> monitor.
>>
>> My goal is to verify the boards / monitor as good before I being the
>> recapping process.
>>
>> I verified the board set as working after some initial debug -
>> displaying the vector graphics on my Oscope (see thread above).
>>
>> I received a untested G08 by Fedex ground a week or so ago and began
>> debugging it Sunday. Initially; the monitor did not power up; and I
>> detect both F400 and F401 as blown. I immediately checked the Deflection
>> transistors and detected two of the transistors were shorted. I replaced
>> them with NTE388 (subs for MJ21196G according to Bills Classic Arcade
>> http://www.biltronix.com/Star_Trek_08.html ) on a quick run to Frys
>> Electronics.
>>
>> I replaced the F4xx fuses with 4A Slow Blow as suggested by Bill and
>> F700/600 with 2A slow blows.
>>
>> The monitor powered up and is vectoring the game; however, it only
>> appears to be rendering a "zoomed in" image. IE I can see part of the
>> sega banner and other graphics such as the plasma shots coming from the
>> Klingons in attract mode.
>>
>> I've checked the transistors in the deflection portion of the deflection
>> board and they seem to be good based upon the dmm diode test.
>> I've measured most of the voltages except HV. +9.1 is a little low at
>> 8.5V. +400 is low at around 350V but varies based upon vector images. But
>> unsure that those would be the cause of the image issue.
>>
>> I'm not 100% sure as it's difficult to determine but it looks like the
>> horizontal MAY be ok / unzoomed... and only to vertical is zoomed.
>>
>> I'm looking for suggestions as to what to check.
>> John
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>> chris@westnet.com
>
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Received on Wed Feb 23 23:26:40 2011