Re: Tech : Electrohome G08-003 image too big

I recapped my Monitor today; of the caps replaced C401 and C402 were
replaced.
However, my +126V is still low at about 100V or at least it's barely in
ranges you guys speced.

Should I be concerned with the lowish 126V even tho the screen looks good?

-----Original Message-----
From: Zitt Zitterkopf
Sent: Friday, February 25, 2011 11:45 PM
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: Tech : Electrohome G08-003 image too big

Mark / Teeray,
Much thanks for your help.
I still haven't figured out what is up with my HV section; but I was able to
figure out that Teeray was right with regards to the XY game board issue.

I pulled the XY boardset an started looking for damage / burnt components.
It was then I saw a stray piece of solder about 0.5" long resting neatly
between two ICs on one of the XY boards. EeEeK. I removed it and it appears
the temp solder bridge wasn't enough to damage any components.

Checked with the oscope; and it looked good on screen. Powered up on the
monitor... and the arcade repair gods smiled upon thee.

Check out my worklog at:
http://www.austinmodders.com/modules.php?name=Forums&file=viewtopic&p=25887#25887
to see pictures of the working unit.

John

-----Original Message-----
From: teeray
Sent: Friday, February 25, 2011 2:24 AM
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: Tech : Electrohome G08-003 image too big

Listen to what the man is saying.

><<Does adjusting X and Y on the game board have any effect>>
>
>No noticeable impact in the Y. X does seem to shrink the horizontal.
>
>>> 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.
>>>

This is a problem with the game board.
The Y amp circuit.
I bet when he displayed it on his O'scope he had the volts per division
for Y set different from X.
exp. X set to 2V/D y set to 4V/D
to make it look OK on the scope.

Tim

-----Original Message-----
>From: Zitt Zitterkopf <zittware@hotmail.com>
>Sent: Feb 24, 2011 11:47 PM
>To: vectorlist@vectorlist.org
>Subject: Re: VECTOR: Tech : Electrohome G08-003 image too big
>
>Pin8 varies based upon the screen content. I've seen it as low as ~93V and
>as high as ~104V. On average it seems to be about 96V.
>
>I pulled the small board and measured transistors, resistors, and diodes.
>Resoldered some pins with minimal solder. No change.
>The pot on the small HV board does not seem to impact the image much.
>
><<Does adjusting X and Y on the game board have any effect>>
>
>No noticeable impact in the Y. X does seem to shrink the horizontal.
>
>John
>
>-----Original Message-----
>From: Mark Jenison
>Sent: Wednesday, February 23, 2011 10:35 PM
>To: vectorlist@vectorlist.org
>Subject: Re: VECTOR: 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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Received on Fri Apr 8 00:33:02 2011