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Atari 7800 pot replacements


fille1976
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It was not clear if by too big you meant physically or the value, if physically and they cannot be adjusted without removing the case then you are looking for a preset potentiometer a.k.a. Trimmer which are small and meant for occasional adjustment for fine tuning as opposed to a regular pots which will be large and mean to be used more frequently i.e. paddle conrollers/volume control.

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i believe 1 is for a7800 mode and the other is for a2600 mode,both color adjustment.

bestelectronics sended me 2 new,but they are too big for install.

also those 2 ic beneath c398052-001,they dont match what is on my pal 7800 mainboard.

it will be the last time i ordered there,i sended a pictures of all the ic's.

and then they sended me 2 ic'c that dont match.

can someone say what they are.

grts filip

2ltm2om.jpg

Edited by fille1976
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i clearly said its a french rgb model 7800 and thats its pal version.

and my board is at my installer now.

i asked my installer to took pictures,then i sended brad them.

so now i have ic's that doesnt match to those on my mainboard.

im not so happy with this situation.

Edited by fille1976
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Googleing PAL 7800's, the pot's in the photo's do look smaller than on the NTSC version. You should contact Brad to let him know the mistake and request he send out new ones. I don't think there were different versions of the CPU and RIOT for PAL and NTSC, so the lower two IC's in your photo should be ok.

 

edit: I just looked up the French SCART version. Looks like Atari used UMC brand parts that didn't have Atari p/n's on them.

 

your board

UM6502I = C014806 Atari part

UM6532 = C010750 Atari part

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ok,will ask them in a mail,but its not funny.

but once i got everything all will be fine,dont wanna stress for this.

but my installer must be 100% sure its fine to install those ic's,or else maybe bye a7800.

and its a fine system that i dont want to loose.

Edited by fille1976
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From http://faqs.cs.uu.nl/na-dir/atari-8-bit/faq.html

On the 6205 "Sally"

 

Several manufacturers produced the SALLY 6502 for Atari, including MOS
Technology, Synertek, Rockwell, NCR, and United Microelectronics (UMC). It is
important to note that chips marked "6502C" such as the MOS Technology
MCS6502C, MOS Technology MPS6502C, Synertek SY6502C, Rockwell R6502C, or UMC
UM6502C are NOT the Atari "6502C" --these are all equivalents to the standard
MOS Technology MCS6502. Atari SALLY 6502 chips are never marked "6502C" but,
other than the UMC UM6502I, always carry the Atari part number C014806.

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so the parts seems to be fine then that i ordered.

he just have to know where to solder them.

i asked him to solder first in a socket and put them in there.

easy if something broke,easyer then desoldering.

Great idea to put in sockets when you are removing IC's.

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  • 4 weeks later...

Hi All,

 

I am the one doing this job for the op. Originally it was just supposed to be remove some chips and fit some sockets, but it being a french console has caused some confusion by the look of things.

 

Here is a list of the chips I have been sent via the op (they ordered them direct to me):

 

C398052-001 which is the tia and DOES match the existing chip in the console

C010750-12 or R6532-15 - I assume this is the riot and I ASSUME it matches the UM6532 that is originally installed in the console.

and finally a chip labelled 8250 and C014806-03 which is the CPU. This DOESNT seem to match whats installed in the console (UM6502, 9137S, 819580)

 

There is no replacement for the maria in the items ive been sent.

 

Does anyone know if the CPU is compatible? or is this specific to this console and a different replacement is required?

 

Thanks

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It is difficult to tell from the images in which way the trim post are too big, there are generally two types of pin spacing, one is an equalateral triangle where the third pin is the same distance from the other two as the distance between those two pins and the other has the third pin slightly further away (by about 0.1", 2.5mm) from the other two then the distace between them.

Is the pin configuration the problem or are they physically to big in that the body interfeers with other nearby components? ​Either way other types of trimmer and pin spacings are available that will fit and should be easily obtainable from any electronic retailer but it may help the person who sold them to understand the issue if you told them which (pin configuration or physical size) is the problem.

 

As for the C012806-03, I tried a quick internet search but the only relevent and clear information I could find was here, which indicates that is a Sally chip although I have no idea how accurate that information is.

Edited by Stephen Moss
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The C012806-03 is a Sally. The question then is whether or not the UM6502 is a Sally. It won't damage anything to put the Sally chip in a non-Sally machine, so it doesn't hurt to try it. It just may not work. You probably should replace everything but the CPU first to see if that fixes the machine. If it does, then try the new CPU if you really want a new part in there. You can always go back to the original if it doesn't work.

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Hi,

 

Thanks about the info on the chips.

 

Regarding the pots, both the layout and the physical size are off. I couldnt find any direct matches on rs, but happy to be proven wrong. I did find some that look like they will be a better fit, but if someone knows of one that looks near original - that would be prefered. I am sure they exist, I am just not finding them easily.

 

Here are some pics of the original pot vs the replacements I was sent.

 

IMG_20170323_155331.jpg

 

 

IMG_20170323_155351.jpg

 

IMG_20170323_155403.jpg

Edited by Bad_Ad84
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