Help Identify Monitor

[FrizzleFried]

I just picked up a cabinet for $40 + some DVDRs...it came with the following monitor.  The actual "houseing" of the monitor says it is an Electrohome G07 but it looks NOTHING like the G07 I have...nor does the screen or PCB look 25 years old.   The damn thing looks pristine!  Not a single bit of burn-in and as I said the PCB is actually somewhat CLEAN.

Anyone have an idea of what the monitor is:









Thanks!

[FrizzleFried]

Ah!  It's a PROMAX g07 replacement...according to the photo at The Real Bob Roberts:



Is this GOOD,  BAD,  or SO-SO?

[Ken Layton]

Yes that's a "Promax" which is in reality a Wei-ya brand and it's model 320-H.

[FrizzleFried]

Ken,

It works...

One helluva find I think for the money!   What is your opinion of this chassis?   Any resources you know of to learn about it?

There are 3 pots on the board itself that i'd love to know what they do.  Toward the left.


Thanks!

[Kevin Mullins]

Generally speaking when you find pots  in "three's" like that each with it's own transistor and resistor sets they are color related. Probably Red Green Blue color gains/drive.

Those have a remote board with the adjustments for brightness, contrast, vertical/horizontal hold , etc right?

[FrizzleFried]

Kevin,

Correct...it does have a remote board.  There is also a single pot toward the top right of the board but more centrally located.  It seems to have an effect on the horzontal movement...I don't have a mirror set up so I am just adjusting and then looking so I can't really be certain.

On my G07 there is a pot for the B+ that is supposed to be set to 120v...does this chassis have one of those and where would I measure to set it?

Also,  my G07 required a sync mod to get rid of the curl toward the top of the monitor,  do you know if these monitors experience similar curl...from the BLANK image i am getting,  I am getting a little of that curl..and I am having difficulty getting it to fill the screen vertically...I got it to go all the way across and from the bottom to about 85% up...

I am sure it is just an adjustment issue.  I also need to replace the rightmost pot on the neckboard (Red i think)...it was bumped and broke.

Again...any and all help/info on this chassis would be of great help.  There is VERY little that I can find online.

Thank you.

[Ken Layton]

Try this:

http://arcarc.xmission.com/PDF%20Monitors/Eygo%20chassis%20Replacement%20for%20G07.pdf

[FrizzleFried]

Thank you Ken for that information.  It will certainly come in handy when I am ready to wire up the monitor...especially since I will be change it to a vertical orientation.

There doesn't seem to be any indication what the pot toward the middle-right rear is...

Any idea?

Thanks!

[Kevin Mullins]

That other mystery pot is in the vacinity of the power supply section (the four diodes in that area would be the bridge rectifier you see in the schematic) and the schematic Ken gave ya shows a VR502 in that area.... should be the B+.

Would think you could measure the B+ off the leg of R502 (2.2k 2w resistor).
But I wouldn't mess with it if it's working and there doesn't seem to be an actual specification to go by to set it.

[FrizzleFried]

Kevin, 

It "works"...does the same thing the B+ does on the G07...it sort of "collapses" and "expands" the image some..

It would be REAL NICE to find out the spec on this and set it accordingly.   I fear that I am running too much power through the circuits.   Perhaps I will check it and decide from there what to do...120V may be the way to go.

[Ken Layton]

The vast majority of normal 19" raster arcade monitors use 120 or 123 volts DC as the B+ voltage. Usually 25" monitors use 130 volts.

[FrizzleFried]

After comparing the schematics with the actual board,  the POT I am referring to which is think is the B+ is listed as VR101,  not VR502.   I can't even find a VR502...I found an empty space labeled VR501 up front.

So if VR101 is the pot I think is B+,  could I measure at the large white thing that is labeled R102?  It looks similar to the component I measured the B+ off of on my G07.

Here is an image showing the POT that is labeled VR101 and the two items I am questioning if I should check for the B+ voltage.

Please be patient with me...this is ALL NEW to me...I don't have any training in reading a schematic.

Best to ASK ASK ASK I always say.




EDIT: Ah!  There is an R101 up there as well...another white semi-long thing...situated just north of the horizontal thing I put the "??" on.   I am guessing VR mean Voltage Regulator?  R means resister? 

[SirPeale]

EDIT: Ah!  There is an R101 up there as well...another white semi-long thing...situated just north of the horizontal thing I put the "??" on.   I am guessing VR mean Voltage Regulator?  R means resister? 

VR = Variable Resistor.  That's what a potentiometer is. 

[FrizzleFried]

Alright...a couple things I notice...

I tried to measure the R102...it shows nothing....

I attempted to get in to R101,  but i shocked the hell out of myself when I touched the actual TUBE.  Is that normal?  I noticed there doesn't appear to be a grounding strip around the tube like my G07 had.  I then touched the tube with the "HOT" end of my micrometer and gounded out the common end and it caused my meter to freak out so I immediately withdrew....

I should be checking for VDC not AC?   Shouldn't the monitor have a grounding strap?   Is it normal for the tube to be "hot" like that?

EDIT: I got up enough balls to go out and mess with it again.  I am not sure what kind of shock that was...but I am not getting a reading on the AC end,  though I DO get a  small spark from time to time at the tip of the hot probe.

I figured I will wait until I get more info on this before i mess with it more.  I'd love to find out exactly where I can test the B+ voltage...

I do see that the jamma signal inputs have been cut off.  Anyone know the name of the connector for the signal input?

Also,  on the chassis there are 6 pins...I only see 5 wires from the jamma connector...red, green, blue (I think i can figure that part out),  grey and black...I assume black is ground?  What is gray?

Finally,  when I rotate the monitor (it is currently horizontal),  do I rotate it clockwise or counter-clockwise while facing the front glass?

THANKS!

I do appreciate the help. 

[FrizzleFried]

...and for the life of me I can not figure our that schematic.  It lists things that don't seem right on the board itself.  For example,  the only other POT other than the RGB adjustments on the board is listed as VR101 on the board,  but I can't find a VR 101 on the schematic.  When I look at the schematic,  the numbers that are close to the v110 source don't appear to jive with the numbers of the components near where the power comes in.   

Argh...also,  it appears the signal input has (R)ed (G)reen (B)lue (V)sinc? and (C)ommon? ...I assume that grey is V and black is C from the jamma harness?   Also,  there appears to be a (H)orizontal? post...what do I do with that...or if I am going vertical do I hook the gray to that?

So many questions...argh.

THANKS!