Let's document the K4900 series medium resolution monitors

I just haven't had the time to put more info into this thread about the 4915/5515s..

Here are some more pics. I appreciate your time.
Thank you.

Ok based upon the following that appears to be a 25K5515 25" medium resolution chassis for say 720 among other games.

1730649815842.png1730649865209.png

The 5515 doesn't have the caps on the back side of the neck board (none of mine do anyway).

I saw the transparent component right by c205 and I have always thought that component was a dead giveaway that the chassis is a medium resolution.
Yes, that's what I've noted but honestly I haven't looked the part up on the schematics and done any validation.

However, it has the WRONG voltage regulator installed as it should have an STR380.

1730649988987.png

The manuals are a tricky bunch because there's lots of errors because these monitors were basically production hacks to make medium res monitors from the std res ones. 5515 manual schematics are wrong and show STR381 and 130v B+..

1730650296658.png

if you go to the parts list and the pin voltages they show the STR380 values of 123v..

1730650194487.png
1730650221111.png
 
Thanks a bunch. I appreciate your help. I found in my stash 4 more boards that are identical to the one I provided pictures of. They all have the same str381 voltage regulator installed as well. I found 2 of the 19 inch medium resolution chassis' as well. One has the caps on the back of the neckboard, the other one does not.
 
Thanks a bunch. I appreciate your help. I found in my stash 4 more boards that are identical to the one I provided pictures of. They all have the same str381 voltage regulator installed as well. I found 2 of the 19 inch medium resolution chassis' as well. One has the caps on the back of the neckboard, the other one does not.
I have run into this as well.

The easiest way to tell if it's a Med Res is the voltage regulator being STR380.

I have a couple of 25" that I though were med res, but ended up being std res with STR381 VR's.
 
I have run into this as well.

The easiest way to tell if it's a Med Res is the voltage regulator being STR380.

I have a couple of 25" that I though were med res, but ended up being std res with STR381 VR's.
Thanks. Do any of your 25"s standard also have the transparent component?
 
The easiest way to tell if it's a Med Res is the voltage regulator being STR380.

I've not found this to be true. The regulator could be anything since the manuals are full of errors so I've seen them mixed up several times.
I've seen 19k4915s run with STR381s as well as a chassis with a regulator labeled as an STR380 which was regulating at 130v (did the same in multiple chassis).
 
Is there a good way to tell if a 19" k4900 is medium res or not? I'm trying to find my Toobin and Super Sprint chassis' among my large stash of them.
 
Is there a good way to tell if a 19" k4900 is medium res or not? I'm trying to find my Toobin and Super Sprint chassis' among my large stash of them.

As you mention games that take a 19" monitor I'll assume you're looking to find 19k4915s...

Look for an STR380 voltage regulator, a tall WHITE width coil (used in 25" games), the protection board, RC network, and 2 white ceramic power resistors (one inboard, one outboard) mounted on the chassis frame near the VR, a modded in 680ohm 5w resistor just behind the 5th pot board. The following shows a few of these marked up.

1732067374695.png

See posts 1-2 to get more pics of a 19k4915 showing these features.
 
Now I didn't stop to read the entire post. But from my experience any mid rest tube that is 19 in or 25 in needs to end in WOOX. My Star Wars stand up my paperboy and my Star Wars cockpit that has a 25 in them all tube numbers end in WOOX. Again I didn't read the whole post so I'm not sure if I'm just repeating what somebody else said but in the 40 years I've been doing this that's what I found the dot pitch is different and the graphics are definitely better with a WOOX tube.
 
Now I didn't stop to read the entire post. But from my experience any mid rest tube that is 19 in or 25 in needs to end in WOOX. My Star Wars stand up my paperboy and my Star Wars cockpit that has a 25 in them all tube numbers end in WOOX. Again I didn't read the whole post so I'm not sure if I'm just repeating what somebody else said but in the 40 years I've been doing this that's what I found the dot pitch is different and the graphics are definitely better with a WOOX tube.

I had always understood the 1st three numbers designated the resolution and size of the tube. So M48 was Med Res. And as such med res tubes were not used in all Med Res monitors: If you have Tube spec sheets available from the MFG please post so that I can better understand the part #designation.

The WG19K4915 monitor in OEM config used the Rauland M48 (med res) tubes.
1700344162262-png.704583


The WG 19K7635 monitor in OEM configuration used a A48ACB (std res) tube.
1700344200027-png.704584


19" Amplifone monitors were shipped OEM with the M48 tubes. However, depending on the manual you open it specifies both M and A tubes. There were A series tubes that were provided as replacements by Atari. The 25" doesn't specify a resolution. Here's an example from TM-194 2nd printing:
1742300331745.png
 
So, I guess I will post this here. There is no one place, that I can find, that documents the yokes for the 4915, 5501, and 5515. From what I have found, I think this is correct, but I don't have the impedance from the yokes that I would like to add to this repository.

4915: Yoke Part#: 9A2844-001 -- (Is this correct @bakerhillpins, on post #6 I was assuming you were talking about the 4915)
5501: Yoke Part#: 48007129 or 9A2870-001 (this is just from a wanted post in 2008) can anyone verify this?)
5515: Yoke Part#: 9A2870-001 (modessitt was asking to borrow one for a 5515, however he says the standard rez version will not work, which is the same part #, and Atari TM-295) Will need some verification here
Atari Manual for Medium Rez 4915: Yoke Part# 9A843-001

So there is conflicting info here on the 4915, and I'm wondering if the 25in version is the same? (different part #s for the med rez version and standard).
 
Sorry, soooooo busy with other life things this year.

4915: Yoke Part#: 9A2844-001 -- (Is this correct @bakerhillpins, on post #6 I was assuming you were talking about the 4915)
Yes, that's the yoke I have pics/measurements of on post #6

5501: Yoke Part#: 48007129 or 9A2870-001 (this is just from a wanted post in 2008) can anyone verify this?)
It does seem like this yoke has turned up as the same on both of these monitors in one or 2 posts. However, there is very scant info out there.

Atari Manual for Medium Rez 4915: Yoke Part# 9A843-001
I know this is late but you should post up images from the manual pages. That PN is too short BTW.

5515: Yoke Part#: 9A2870-001 (modessitt was asking to borrow one for a 5515, however he says the standard rez version will not work, which is the same part #, and Atari TM-295) Will need some verification here
Again, having a pic of the page from the manuals just saves us all a lot of time digging.


The real problem here is that there are SO many errors in the Med Res manuals. It's hard to tell what's correct.
 
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