Vectorlist Archives: Re: Tech : Electrohome G08-003 image too bi

From: Zitt Zitterkopf <zittware_at_hotmail.com>
Date: Tue Apr 12 2011 - 01:54:29 EDT

Mark,
Thanks.
Assuming it does adjust - what is the impact of increasing the +126V?
What should I set it to?
John

-----Original Message-----
From: Mark Jenison
Sent: Sunday, April 10, 2011 8:09 PM
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: Tech : Electrohome G08-003 image too big

The +126V is controlled by that little satilite board on the HV cage; try
adjusting it and see what range you get.

----- Original Message -----
From: "Zitt Zitterkopf" <zittware@hotmail.com>
To: <vectorlist@vectorlist.org>
Sent: Thursday, April 07, 2011 11:31 PM
Subject: Re: VECTOR: 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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Re: Tech : Electrohome G08-003 image too big