400- no memo pad- help please

[mimo]

I have been trying to get my dead 16K 400 up and running.

I have found by swapping parts off my good 48K 400 that I need a new RF box (PAL)

now that I have got a picture, the memo pad does not come up when booting without a cart, and there is no key-klick or keyboard activity.Any ideas where I should be looking next? my guess is something OS related.

I have managed to have a nice game of Miner 2049'er

 

Also, anyone know how to do a 48K or 64K (or more) upgrade, so I can use it with a disc-drive, APE etc.

 

Thanks

Edited May 17, 2007 by mimo

[Rybags]

So, you're saying that game carts still work?

 

Kinda strange.

 

The OS is at least functioning to the extent that carts work... and both the "E" and "F" ROMs would have to be OK in order for that to happen.

 

What about something like just the BASIC cart?

[mimo]

not got basic working, but I will have another go tonight, had to pack everything away while I look after my 2 kids, and go to work later

[mimo]

Basic does not work, it is fine on my other 400,

the problem 400 is now having problems with video output as well, with the RF box off the good one.

Think i'm going to call it

 

Time of death...............

[re-atari]

Basic does not work, it is fine on my other 400,

the problem 400 is now having problems with video output as well, with the RF box off the good one.

Think i'm going to call it

 

Time of death...............

Hold your horses before you decide to put it in the dumpster.

I'd give it another go by checking the PSU's voltages, and if the correct voltages actually get to the IC's on the mainboard and cards. I have experienced some weird errors due to dried out capacitors in PSU's, so visual inspection and replacing any suspect ones can't hurt. Did you already reseat the socketed IC's?

 

re-atari

[mimo]

Re-seated and swapped the IC's, The PSU is fine, well it works fine with my other 400 and 1050.

I am open to any other ideas.

Also I have a problem of only 1 PAL RF PCB and components for 2 computers!

If I can make it live again I really want to

[re-atari]

Re-seated and swapped the IC's, The PSU is fine, well it works fine with my other 400 and 1050.

I am open to any other ideas.

Also I have a problem of only 1 PAL RF PCB and components for 2 computers!

If I can make it live again I really want to

I'm afraid I'm not familiar with 400/800's, only XL's, so my tips were pointing at the ususal suspects in general.

 

Do you have any experience with a soldering iron?

If the mainboard and slot-in PCB's contain electrolytic capacitors, you might want to check them visually. The ones that are swollen or have leaked fluid onto the PCB will have to be replaced. Such caps will, when being desoldered, smell like rotten fish (really, I'm not joking!). If that's no avail, you could have a go at resoldering the slot connectors for the carts and the PCB's. After that, I'm afraid replacing support IC's is inevitable, since you don't get into Basic or Memopad I'd start with the ones in the address decoding circuitry.

BTW: you do have the schematics? The DL-link for them has been mentioned recently in a number of posts dealing with repair subjects.

 

As for me, I would not hesitate to replace all 74LSxx's and CD40xx's and soldering in sockets, just for the fun of it. If you care to go that route, it might be easier to just snip off the IC's you are going to replace, and clean up the solder eyes with desolder wick. This will prevent damage to the PCB like lifted traces. All in all a bit crude and time consuming, I must admit.

 

re-atari

[mimo]

Re-seated and swapped the IC's, The PSU is fine, well it works fine with my other 400 and 1050.

I am open to any other ideas.

Also I have a problem of only 1 PAL RF PCB and components for 2 computers!

If I can make it live again I really want to

I'm afraid I'm not familiar with 400/800's, only XL's, so my tips were pointing at the ususal suspects in general.

 

Do you have any experience with a soldering iron?

If the mainboard and slot-in PCB's contain electrolytic capacitors, you might want to check them visually. The ones that are swollen or have leaked fluid onto the PCB will have to be replaced. Such caps will, when being desoldered, smell like rotten fish (really, I'm not joking!). If that's no avail, you could have a go at resoldering the slot connectors for the carts and the PCB's. After that, I'm afraid replacing support IC's is inevitable, since you don't get into Basic or Memopad I'd start with the ones in the address decoding circuitry.

BTW: you do have the schematics? The DL-link for them has been mentioned recently in a number of posts dealing with repair subjects.

 

As for me, I would not hesitate to replace all 74LSxx's and CD40xx's and soldering in sockets, just for the fun of it. If you care to go that route, it might be easier to just snip off the IC's you are going to replace, and clean up the solder eyes with desolder wick. This will prevent damage to the PCB like lifted traces. All in all a bit crude and time consuming, I must admit.

 

re-atari

Thanks,

soldering is getting better, this week I have socketed the RAM on a dead (now working) 800 XL and done a s-video mod on a 7800.

I am going to re-trace my steps and try again with the 400 when I get (allowed ) more time.

I really dont want to let this one die