Re: G08 Rebuild issues

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
>>
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>>
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>>
>>
>>
>>
>> --
>> 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"
>>
>
>

-- 
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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