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BeeryMiller

Geneve 9938 issue

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I noticed this issue last spring, and this past weekend, switched things around to confirm.

 

I am not seeing red on my Geneve. Has anyone ever observed a specific color missing to know the likely cause? I pulled up John Strain's schematic from the 9938 to the video port, but have not started testing anything with an ohm meter to see if there is a break in connection yet as I have to find my ohm meter.

 

Any thoughts on a likely failure? I do not know if the video lines run on a layer below the surface, or if they are visible.

 

Any thoughts appreciated.

 

Beery

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Cable OK? Solder joints on the board OK? I had that issue now and then until I made a completely new cable.

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Is the video jumper near the neck of the card set to the right position?

 

I will have to investigate. I looked for a video jumper the other day when I was swapping/testing eproms for Mike, but did not see a jumper. Guess I need to take another look.

 

Beery

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Thanks for the information. I guess I will have to squint a bit more to confirm the pin selection. As this Geneve was given to me something like almost 5 years ago, I assumed it had been properly configured since it was an RGB monitor that was being used. In hindsight, that may have been an error on my part and the previous owner may have had it improperly configured for all these years.

 

I will know the answer in about 4 hours.....

 

Beery

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I will have to investigate. I looked for a video jumper the other day when I was swapping/testing eproms for Mike, but did not see a jumper. Guess I need to take another look.

 

Beery

It's close to the 8 pin DIN and easy to miss. Hopefully that's all it takes to resolve.

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Does anyone know of a reliable source to purchase a couple of 9938 video chips. I bought one from china a few months ago, and believe that I documneted a failure here on atariage concerning it. But that chip I believe caused a new ram chip to go bad and even after replacing the ram chip the 9938 is showing artifacing all over the screen. But when I put a known good 9938 onto the board the artifacting is gone. All the ones I see on ebay are from china, so does anyone know of a source here in the states? Thanks

Edited by RickyDean

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Well, I bit the bullet and purchased two more 9938's from China, 1 came in Friday, waiting for the other.

But that being said, the one that came in Friday is not operational, and I expect that the one coming in behind it will be no different.

They were both purchased from the same seller on ebay, but not the seller that the prior bad 9938 was purchased from a few months ago.

If this next one does not work, I will attempt to modify a 9958.

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Well, I bit the bullet and purchased two more 9938's from China, 1 came in Friday, waiting for the other.

But that being said, the one that came in Friday is not operational, and I expect that the one coming in behind it will be no different.

They were both purchased from the same seller on ebay, but not the seller that the prior bad 9938 was purchased from a few months ago.

If this next one does not work, I will attempt to modify a 9958.

Slightly OT, but did you pay (or is anyone else) pay premiums (tariff increase or actual customs fees) on China orders lately? Jameco, Digikey, and a few others charge up front, but so far Ebay hasn't tagged me though I try to keep restock orders on my parts bins under $100 actual value.

Just curious.

 

Doug

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Slightly OT, but did you pay (or is anyone else) pay premiums (tariff increase or actual customs fees) on China orders lately? Jameco, Digikey, and a few others charge up front, but so far Ebay hasn't tagged me though I try to keep restock orders on my parts bins under $100 actual value.

Just curious.

 

Doug

Sorry for the delay, helocast. No so far I have just made offers or paid the price listed on Ebay. I too, have paid some surcharge to Jameco, but not Mouser as of yet. Haven't done any business with Digikey recently. My question is why does a chinese seller, sell a product that will not work from the moment it is installed, where is the financial gain from that when I am just going to ask for my money back. I have waited patiently for this to arrive, just to discover from the get-go, it is worthless.

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Well, I finally found a 9938 on ebay from an usa seller, and when I installed it, my Geneve came up without artifacts, just need to get the drive reinstaled tonight and see if it boots fine.

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I was able to obtain two more good V9938's so I can start working on my other Geneve's now, Happy... Happy...😃

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Let me try again, if one needs to buy working 9938's where does one go? 😃

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@dhe, finding a seller with good 9938s is a matter of luck. The last ones were working pulls, and all came from a single source (who doesn't have any more available at the moment), but the userID is: gameboardsoc1234. 

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I guess given my own recent issue with cc-40 memory upgrade chips and what I'm reading in a number of threads on this forum... When getting CFC (Chips from China) to attempt a repair, one should take each chip with a grain of salt and either check it in a working unit or in a tester, before trying to use it in a repair to save hair pulling....

 

Getting a sealed and tested chip from Newark is now a thing of yester year.... =(

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12 hours ago, dhe said:

Let me try again, if one needs to buy working 9938's where does one go? 😃

Oh, I'm sorry Dan, I was getting ready to leave work and go home in rain and storm, so wasn't thinking about that. If you need one badly, I can let you get one of mine?

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32 minutes ago, dhe said:

I guess given my own recent issue with cc-40 memory upgrade chips and what I'm reading in a number of threads on this forum... When getting CFC (Chips from China) to attempt a repair, one should take each chip with a grain of salt and either check it in a working unit or in a tester, before trying to use it in a repair to save hair pulling....

 

Getting a sealed and tested chip from Newark is now a thing of yester year.... =(

Yea, and I am also thinking some from China may be rebranded v9958's but haven't tried to wire on up yet to see, but they don't work as 9938's that their labeled as.

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Unicorn Electronics has good chips that work first time, every time. Their minimum order (for free shipping) is $30. If you need a very small order, they are also HODGE16 on eBay. The prices are a bit more but they will combine shipping charges if you ask.

 

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