130 XE - No Video Output / Boot Up

[BeaglzNZ]

I have picked up a 130 XE but I am not getting any video output (from the monitor socket).

 

Luckily most of the key ICs are socketed and the CPU has been tested and is working. I have dropped in a new ANTIC and GTIA but still getting no video output.

 

Have checked that there is 5v across Capacitor 2 and 5V also seems ok on the chips.

 

Unfortunately the memory chips are not socketed - would the computer still boot up if memory chips were faulty - would be surprised if they are all faulty. Using the on board memory test would identify problem chips.

 

Any suggestions on tracking down the culprit part(s) - capacitors look ok from a visual check. I know the keyboard isn't 100% but my other 130XE boots up without keyboard connected (alas its components are not socketed so cannot swap parts to eliminate the good from the bad).

 

[+Nezgar]

Any clicks or pops at least from the monitor audio out when turning on?

Yes bad memory could give you a black screen. Even if only 1 of the 8 chips are bad.

Are you able to swap the OS ROM? ( CO61598B ) Been some threads about those bad too recently.

Sys-Check 2 will confirm quickly for sure either of these issues if you have it... (or something to consider) : http://atariage.com/forums/topic/251315-sys-check-v22-ready-to-use-batch-available/

 

Replacement RAM is cheap, but it will be some work to replace since not socketed...

 

OS ROM can be replaced with a 27128 EPROM without modification.

[xrbrevin]

MT RAM chips often fail but i just picked up an 800XL with them in and it is a fully working machine (touch wood...)

+1 thumbs-up for Sys-check II - very useful for repairs and also has a RAM upgrade built in!

Edited March 3, 2019 by xrbrevin

[BeaglzNZ]

Thanks for the tips so far - just need to get through the working week and have a look at it on the weekend. Cheers.

[xrbrevin]

if you have spare ram chips, you can piggyback them on the existing chips to diagnose a bad one(s).

[manterola]

Probably RAM. I just repaired an 800xl with soldered mt ram chips. I got 41256, 8 of them very cheap. I also cut the existing ram feet, destroying the Mt ram chips, that way is much easier to extract the chips.

I installed sockets and put the new NEC ram.. I crossed my fingers, and boom... It worked!!. Many here have mentioned that the most likely thing to fail are the MT ram chips.

After that I got a Rambo compatible PCB in oshpark and did the 256kb (quarter mega) ram expansion, but that is part of another story

[DavidMil]

Does your 130XE try to access a floppy drive at boot up? If you hold down the Start button when turning on the computer,

do you hear the long beep that tells you it's trying to load a tape? These two tests can give you an idea of what is working

thereby narrowing the possible problems.

 

DavidMil

[BeaglzNZ]

So far I have swapped out the CPU, Antic, GTIA, PIA & Pokey with a working 800XL and they all work.

Tried piggy backing a memory chip but no difference.

Tried to burn a ROM onto a NEX 27128 but kept getting programming errors. No problems reading the blank chip.

Tried to read the original OS Rom but again getting 3 pins with errors.

 

Given it has zero video output could it be the MMU?

 

Will look at getting a new 27128 and try programming that as a replacement ROM.

[Mq.]

If you have a black or red screen, then it could be some chip damaged. But if you have no video signal at all, then check 14MHz oscillator. I fixed two dead motherboards by replace oscillator.

[+Nezgar]

Will look at getting a new 27128 and try programming that as a replacement ROM.

If you have a 27256 or 27512 handy to test, you can repeat the same 16K 2 times or 4 times, respectively.

[xrbrevin]

you can burn an MMU chip using a GAL eprom (16V8 i think..)

its in the forums here, just do a search

[BeaglzNZ]

Tried to source some parts from Best Electronics but they have no CO70034 oscillators - bit of a long shot but does anyone have one available or suggest another supplier?

Tried using a logic probe on the memory but not 100% sure what I am looking for - have at least confirmed that the 5v supply is good to all chips. Could possibly be the MMU or Freddie chip (5v good as is ground).

[1050]

Mouser, but there is a 500

minimum order for $615 US and it' a 3.3 volt surface

mount chip.

 

https://www.mouser.com/ProductDetail/IDT/XLH335014187500X?qs=itIaUkCn8qCHxcNd7YFfTw%3D%3D

 

Alibaba

https://wtlcrystals.en.alibaba.com/product/60813231349-220265491/WTL_HC_49S_Xtal_Resonator_Quartz_Crystal_14_187576_MHz.html

 

Nothing else out there, best of luck.

[+Stephen]

Tried to source some parts from Best Electronics but they have no CO70034 oscillators - bit of a long shot but does anyone have one available or suggest another supplier?

Tried using a logic probe on the memory but not 100% sure what I am looking for - have at least confirmed that the 5v supply is good to all chips. Could possibly be the MMU or Freddie chip (5v good as is ground).

Try asking AA user MacRorie (from the brewing academy) - he's selling parts to build complete Atari clones in PAL. I'd guess he has a suitable replacement for you.

[Mq.]

Tried to source some parts from Best Electronics but they have no CO70034 oscillators - bit of a long shot but does anyone have one available or suggest another supplier?

Tried using a logic probe on the memory but not 100% sure what I am looking for - have at least confirmed that the 5v supply is good to all chips. Could possibly be the MMU or Freddie chip (5v good as is ground).

You have to looking for normal crystal 14,187576 and not for integrated oscillator/generator.

Anyway it's hard to find and buy it, then you should be sure it is damaged before you ride the long way round the world to find it:-)

You must to check it by oscilloscope or logic analyser or frequency meter. Just check if there is any clock signal around the Freddie chip.

[BeaglzNZ]

Any clicks or pops at least from the monitor audio out when turning on?

 

Yes bad memory could give you a black screen. Even if only 1 of the 8 chips are bad.

 

Are you able to swap the OS ROM? ( CO61598B ) Been some threads about those bad too recently.

 

Sys-Check 2 will confirm quickly for sure either of these issues if you have it... (or something to consider) : http://atariage.com/forums/topic/251315-sys-check-v22-ready-to-use-batch-available/

 

Replacement RAM is cheap, but it will be some work to replace since not socketed...

 

OS ROM can be replaced with a 27128 EPROM without modification.

 

If I get a Sys-Check II will it run the tests despite no video output - does it run off its own memory so in effect bypassing the computer memory for boot up? Not really keen on spending NZ$100 for something that isn't going to help me. Best Electronics also have a diagnostic cartridge but is limited to the 65/130xe but also tests some other things.

[+Nezgar]

If I get a Sys-Check II will it run the tests despite no video output - does it run off its own memory so in effect bypassing the computer memory for boot up? Not really keen on spending NZ$100 for something that isn't going to help me. Best Electronics also have a diagnostic cartridge but is limited to the 65/130xe but also tests some other things.

 

Sys-Check II indeed does much more than any diagnostic cart can, and has benefits even for working machines.

 

• One DIP switch will disable the internal 64KB RAM and use the RAM on the sys-check instead, otherwise, it provides 512KB of extended RAM which can be used for RAMdisks, and 130XE style extended memory software (and modern demos)
• Another DIP switch disables the internal OS, and another DIP switch selects between 1 of 4 programmed OS's on the Sys-Check.

So with it attached, you can immediately see if the rest of the system is working with RAM and OS are supplanted. If you get the tester showing on the screen, then you also know your GTIA, ANTIC, and CPU are OK. It will work on 600XL, 800XL, 800XE, 130XE, and 65XE with ECI port. (will not work on 65XE with no ECI, 1200XL, or XEGS)

 

Current manual with all the details is here: http://www.van-radecke.de/SysCheck/Sys-Check_V2_2.zip

Nir Dary did a youtube video:

 

Quoting the overview from the manual:

The Sys-Check V2.2 external device offers this major functions:

1. Diagnostic tool for dead computers without the need to open the case
2. External O.S. (operating system) switcher (up to four O.S. can be selected by user)
3. You can also put any standard ROM or EPROM containing Atari O.S.(s) in the DIP socket at Sys-Check´s PCB
4. External 512 KB Standard memory expansion using „RAMBO“ scheme
5. All future updates of the diagnostic tools can be easily flashed into the Flashchip with an easy-to-use flashtool using your Atari XL or XE

[BeaglzNZ]

 

 

Sys-Check II indeed does much more than any diagnostic cart can, and has benefits even for working machines.

 

• One DIP switch will disable the internal 64KB RAM and use the RAM on the sys-check instead, otherwise, it provides 512KB of extended RAM which can be used for RAMdisks, and 130XE style extended memory software (and modern demos)
• Another DIP switch disables the internal OS, and another DIP switch selects between 1 of 4 programmed OS's on the Sys-Check.

So with it attached, you can immediately see if the rest of the system is working with RAM and OS are supplanted. If you get the tester showing on the screen, then you also know your GTIA, ANTIC, and CPU are OK. It will work on 600XL, 800XL, 800XE, 130XE, and 65XE with ECI port. (will not work on 65XE with no ECI, 1200XL, or XEGS)

 

Current manual with all the details is here: http://www.van-radecke.de/SysCheck/Sys-Check_V2_2.zip

Nir Dary did a youtube video:

 

Quoting the overview from the manual:

The Sys-Check V2.2 external device offers this major functions:

1. Diagnostic tool for dead computers without the need to open the case
2. External O.S. (operating system) switcher (up to four O.S. can be selected by user)
3. You can also put any standard ROM or EPROM containing Atari O.S.(s) in the DIP socket at Sys-Check´s PCB
4. External 512 KB Standard memory expansion using „RAMBO“ scheme
5. All future updates of the diagnostic tools can be easily flashed into the Flashchip with an easy-to-use flashtool using your Atari XL or XE

 

 

Great stuff - so much for trying to save some money this year and not ordering retro stuff!

[BeaglzNZ]

Bit of an update (or plea for help rather):

 

My Sys-Check 2.2 finally arrived and have plugged it into the 130 XE and .... no display! Bugger!

 

Checked the 5v wire on the Sys_Check board and the 5v is there so some good news.

 

I have confirmed that the CPU, ANTIC, GITA, PIA & POKEY are all good by swapping them into a working 130 XE.

 

Can look at programming a GAL16V8 to replace MMU? Otherwise de-solder all the RAM and replace?

[BeaglzNZ]

Have just tried burning a new OS and that has made no difference either.

[_The Doctor__]

verify sys check is working on know good machine....

 

if it works, then your malfunctioning computer may have dead component that is shorted, disconnected (open for some reason) I will take it for granted you've already verified power under load and monitor wire/ channel selection as well

[xrbrevin]

attached is the MMU code for the GAL16V8

Atari MMU (C061618).zip

[BeaglzNZ]

verify sys check is working on know good machine....

 

if it works, then your malfunctioning computer may have dead component that is shorted, disconnected (open for some reason) I will take it for granted you've already verified power under load and monitor wire/ channel selection as well

 

Yep - Sys_Check works fine on my other 130 XE.

Tried monitor output as well as RF output and no signal.

Slowly running out of components to check - will try the MMU tomorrow.

[BeaglzNZ]

Programmed a GAL16V8 this morning and as far as I know it has programmed fine but no difference to video output. Dug for some more info on the Freddie chip and CLK seems ok on input but not pulsing on output.

If it was a memory problem I thought the Sys-Check would bypass this and operate - DIP switches are set to do this.

[Mq.]

So check the Freddie chip in another motherboard, probably it is dead Freddie which is common damage.

By the way I told you past before, there is a clock problem if you have no reaction on video output at all.