Re: G08 Rebuild issues

John,

Thanks for taking the time and effort to share the manuals.

Mark

- Sent from my Atari 2600

On Jan 4, 2013, at 1:28 AM, John Robertson <pinball@telus.net> wrote:

> Have uploaded my assortment of Electrohome XY monitors to: (typo fixed!)
>
> FTP site is: ftp://ttl.arcadetech.org/TTL/Test_Equipment/Monitors/ElectrohomeXY
>
> These include four variations of the GO5 and two variations of the GO8 series. Some I have scanned, others are 'found' - where I may have scanned or downloaded over the years.
>
> John :-#)#
>
> John Robertson wrote:
>>
>> OK, here are the adjustments from the Electrohome G08-105 XY November 1982 monitor manual.
>>
>> ----------------------------------------(quote)-----------------------------
>> 4.0 Service Set Up Control
>> NOTE: These controls have been factory adjusted. If adjustment is necessary check set up procedures in this manual.
>> 4.1 G2 Adjustment R930
>> ....
>> 4.8 E.H.T. Duty Cycle R918
>> 4.9 E.H.T. Frequency Adj. R917
>> 4.10 E.H.T. Sensing Control R933
>> 4.11 E.H.T. Regulator Adjustment R945
>>
>> .......
>>
>> 6.0 E.H.T. Alignment (follow this sequence EXACTLY! - JR)
>>
>> 6.1 After 10 minutes warm up, adjust voltage regulator for 100V, -6V/+2V via R945. (JR - I think this is a typo, R310 is the regulator adjustment on version -003) Measurement is made between anode of D902 and ground.
>>
>> 6.2 Jumper TP1 to ground with jumpers hook up oscilloscope to collector of Q902 and adjust R918 for duty cycle of ~ 20 usec on ~ 35 usec off.
>>
>> 6.3 Adjust R917 for anode voltage of 21 KV +/- 300V then remove jumper at TP1 and adjust R933 (R920 for rev -001 - JR) for 0V +/- 15 MV at TP1.
>>
>> Note: Adjustment made with zero beam current.
>>
>> ------------------------(end quote)---------------------------
>>
>> If you do not have these tools or the knowledge of how to use them then send your HV unit to someone who can set it up safely.
>>
>> I've scanned in the manual and will post it to my FTP site (Tech Tools List) later today, and I'll provide the link then.
>>
>> John :-#)#
>>
>> Grant Thienemann wrote:
>>>
>>> Crap yeah I was messing with R917 an R919 on this schematic:
>>>
>>> http://www.arcade-museum.com/manuals-monitors/Electrohome%20G08_Schematics.pdf
>>>
>>> Any help so I can get this set correctly would be fantastic!
>>>
>>> Thanks
>>> Grant
>>>
>>> On Thu, Dec 27, 2012 at 1:19 PM, John Robertson <pinball@telus.net> wrote:
>>>
>>>> Grant Thienemann wrote:
>>>>
>>>> Hey Guys,
>>>>
>>>> Apparently there are two pots on the High Voltage board, what I did to
>>>> fix the problem was rotate them both all the way counter clockwise
>>>> till they stopped, turned on the machine, I finally had a game image
>>>> YES but the screen was small and I had the same issue as before, I
>>>> started rotating both pots very slowly one at a time till the G08
>>>> sounded right, and the game looked great.
>>>>
>>>> I don't think I even needed to rebuild my monitor now that I knew
>>>> about those pots, but I did all the "upgrades" I could find online for
>>>> this monitor and its running VERY well. I don't even here the vector
>>>> chatter that I've heard other people talking about.
>>>>
>>>> The only other "mod" that I'm doing is that my Sega Star Trek has two
>>>> backs on it, and I've left the top one off that is for access to the
>>>> monitor. I figure that will keep the monitor running as cool as
>>>> possible.
>>>>
>>>> Thanks guys!
>>>>
>>>> -Grant
>>>>
>>>>
>>>>
>>>> !!!DANGER DANGER DANGER!!!!
>>>>
>>>> This is potentially a very BAD idea - adjusting various potentiometers in HV
>>>> circuits without the correct test equipment hooked up. Not knowing which of
>>>> the four or so pots on the HV section that you played with, I would say you
>>>> may have created problems/dangers (X-Rays!) for yourself that you may not be
>>>> aware of.
>>>>
>>>> The four pots I find (schematic version G08-003) are R310 (100VDC setting),
>>>> R933, R918 and (danger) R917. At the moment I do not know what R933, R918
>>>> and R917 do, but R917 has a safety mark beside it indicating that it is a
>>>> critical adjustment that likely sets the X-Ray protection circuitry up
>>>> correctly. You REALLY do not want to mess with that with out the correct HV
>>>> probe and other factory recommended adjustment tools handy!
>>>>
>>>> If I have time later today I'll dig into these adjustments, but it would
>>>> help if we knew WHICH pots you adjusted!
>>>>
>>>> Chances are you are safe, but if you set the HV higher than factory AND
>>>> turned back the X-Ray shut-down your tube could be emitting X-RAYS - soft
>>>> X-Rays to be true, but considering people play the game only inches from the
>>>> screen the risk is reasonable that you do nto want to expose yourself or
>>>> loved ones/friends to the risk!
>>>>
>>>> If you adjusted a pot that had any glue or nail polish, etc. to 'lock' it in
>>>> place, then do NOT turn the game on again until you have test gear lined
>>>> up!!!
>>>>
>>>> John :-#(#
>>>>
>>>> On Wed, Dec 26, 2012 at 8:09 AM, Grant Thienemann
>>>> <grant.thienemann@gmail.com> wrote:
>>>>
>>>>
>>>> ok I 'll check both of those, if you think of anything else please let me
>>>> know!
>>>>
>>>> On Tue, Dec 25, 2012 at 5:45 PM, Mark Jenison
>>>> <eliminator4player@gmail.com> wrote:
>>>>
>>>>
>>>> This is another one of those "I've seen this before, wish I had written down
>>>> the fix..."
>>>>
>>>> Offhand, I'd look at the ribbon cable between the xy pair. Then the yoke
>>>> connector.
>>>>
>>>> On Dec 25, 2012 4:36 PM, "Grant Thienemann" <grant.thienemann@gmail.com>
>>>> wrote:
>>>>
>>>>
>>>> Hey Guys,
>>>>
>>>> I did the cap kit on my G08 today, and when I hooked the monitor back
>>>> up to my Star Trek I get scrolling vertical lines. I noticed there
>>>> were two pots on the HV board, and I know I accidentally moved one of
>>>> them when I was rebuilding the chassises, what do those two pots do?
>>>> Its like the horizontal or vertical sync is off, but this is a vector
>>>> not a raster.
>>>>
>>>> Also just messing with it a little bit the more I change the pot the
>>>> more the vertical lines change. Any help would be fantastic.
>>>>
>>>> Thanks
>>>> Grant
>>>>
>
>
> --
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
> www.flippers.com
> "Old pinballers never die, they just flip out"

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Received on Sun Jan 6 12:01:31 2013