130XE - Next up for repairs

[eeun]

Now that the 400 is in good shape, next project is a 130XE with similar issues.

 

I've tried swapping in good PIO and POKEY, but still getting no disk access (or tape, I found another tape drive)

 

It's also got bad ram. With the RAM test showing bad ram like:

 

G G G G G G G G G G G G G G G G

* * G G * * * * * * * * * * * *

G G G G G G G G G G G G G G G G

G = Good/Green, * = Red/Bad

 

...I was able to run Star Raiders cart once I played around with different PIO and POKEY. But only that cartridge would work.

Up to this point, the XE only booted to test mode.

 

I did the piggyback method to test the RAM until I had all Green in the RAM test, then it would boot to Basic, and I could run any cartridge.

But still no disk access! Holding down option at boot takes me to the test mode, as does typing DOS from Basic.

 

The drive and cable are good, the keyboard is good. Solder connections look good around the SIO.

 

Any thought where to look next?

 

And how compatible are parts from the 65XE? I noticed the Antic has a different number between my dead 65XE (12296B) and 130XE (21698).

[Rybags]

Antic not compatable, the 130XE needs the E variant as you listed. Also I believe the 130XE has the EMMU but other XEs only have the standard MMU.

 

Antic would have nothing to do with failed disk accesses anyhow, best to leave it as is. And given the machine seems to work other than the RAM problem, there's probably no point in swapping ICs over.

 

I presume it recognises keypresses if you go to Basic?

 

Given you've tried another Pokey and PIA for the same results, the problem could be with the path from either or both of those to the SIO port.

 

If you've got an Oscilloscope or even just a multimeter, there are some simple tests you could perform.

 

POKE 54019,52 will activate the COMMAND line over SIO, you could test the pin to see if a change is occurring.

POKE 54019,60 or just press RESET to return to normal. Check both, put + to the relevant SIO pin and the - lead of the MM to a ground point on the board.

 

POKE 53775,131 will force the SIO Data Out line to zero, then test the Data Out pin on the SIO port.

POKE 53775,3 or RESET to restore to normal.

 

SIO data out should normally read +5V, and 0V when forced to zero.

COMMAND should normally read +5V and 0V when COMMAND is activated.

 

Also try testing those at the relevant pin on Pokey and PIA. If you get a signal at the chip but not the port, then obviously there's a fault in the signal path.

 

Probably easiest to plug a SIO lead in - it's much easier to test by probing the exposed outer leads on the plug than putting the probe into the SIO port.

 

Pinouts for Pokey and PIA can be found here http://www.atarimax.com/jindroush.atari.org/achip.html

Edited March 6, 2011 by Rybags

[BillC]

Now that the 400 is in good shape, next project is a 130XE with similar issues.

 

I've tried swapping in good PIO and POKEY, but still getting no disk access (or tape, I found another tape drive)

 

It's also got bad ram. With the RAM test showing bad ram like:

 

G G G G G G G G G G G G G G G G

* * G G * * * * * * * * * * * *

G G G G G G G G G G G G G G G G

G = Good/Green, * = Red/Bad

 

...I was able to run Star Raiders cart once I played around with different PIO and POKEY. But only that cartridge would work.

Up to this point, the XE only booted to test mode.

 

I did the piggyback method to test the RAM until I had all Green in the RAM test, then it would boot to Basic, and I could run any cartridge.

But still no disk access! Holding down option at boot takes me to the test mode, as does typing DOS from Basic.

 

The drive and cable are good, the keyboard is good. Solder connections look good around the SIO.

 

Any thought where to look next?

 

And how compatible are parts from the 65XE? I noticed the Antic has a different number between my dead 65XE (12296B) and 130XE (21698).

According to the FAQs CO12296 ANTIC came in NTSC 400/800/1200XL, while the CO21698 came in PAL XL/XE.

[sloopy]

this is a PAL 130XE?

 

either way, first thing to do is fix the ram... its probly micron technology ram which is unreliable... even if you get a good ram test to pass, its still possible it will create problems...

 

also this is an XE board, they are notoriously sub-standard in the quality, do not try to desolder the drams from the board unless you have decent skills with a soldering iron...

 

sloopy.

[1050]

Any thought where to look next?

 

I had a 130XE that would not talk to a disk drive and I wound up cutting the capacitors off the SIO port which got it to rattling on like a gossip over the back yard fence. Got a wad of glass cased capacitors twisted and soldered onto the SIO port lines like a bad after thought? They are right at the SIO jack, you might snip em loose if they are there.

 

Why a capacitor (or several) should interfere with digital commerce like that is not so clear to me, but it sure did the trick that time. Just what they were trying to do by adding them afterwards is also a puzzlement to me, but I'm really not in the loop and I didn't get that memo so SNAFU.

[eeun]

@1050; I had a cleaner version of the capacitors than the rats nest I've seen on others. These were actually labeled on the board around the SIO port. Made no difference.

 

@Rybags; I'm getting a drop on the COMMAND and DATA OUT SIO pins, but discovered my voltages are messed up. My +5V is actually +6.56, and the voltage drop only goes to +0.14. Tried two different power supplies, one rated 9V, the other 7V - not sure which is intended for the XE. Both supplies gave the same +6.56V across the 5V lines.

 

@Sloopy; Ordered some 16-pin sockets from Hong Kong, but my problem is knowing which chips are truly good, and which are merely passing the XE's testing. The RAM I used for piggybacking is from a dead 65XE, so I could be swapping very bad for slightly bad.

[HiassofT]

@Rybags; I'm getting a drop on the COMMAND and DATA OUT SIO pins, but discovered my voltages are messed up. My +5V is actually +6.56, and the voltage drop only goes to +0.14. Tried two different power supplies, one rated 9V, the other 7V - not sure which is intended for the XE. Both supplies gave the same +6.56V across the 5V lines.

+6.5V is way too high - you need a 5V power supply. It could be that you just damaged the good PIA and POKEY...

 

The +0.14V low output is normal, though. Usually you'd see something like 0V - 0.5V for low and 4V - 5V for high.

 

so long,

 

Hias

[russg]

Now that the 400 is in good shape, next project is a 130XE with similar issues.

 

I've tried swapping in good PIO and POKEY, but still getting no disk access (or tape, I found another tape drive)

 

It's also got bad ram. With the RAM test showing bad ram like:

 

G G G G G G G G G G G G G G G G

* * G G * * * * * * * * * * * *

G G G G G G G G G G G G G G G G

G = Good/Green, * = Red/Bad

 

...I was able to run Star Raiders cart once I played around with different PIO and POKEY. But only that cartridge would work.

Up to this point, the XE only booted to test mode.

 

I did the piggyback method to test the RAM until I had all Green in the RAM test, then it would boot to Basic, and I could run any cartridge.

But still no disk access! Holding down option at boot takes me to the test mode, as does typing DOS from Basic.

 

The drive and cable are good, the keyboard is good. Solder connections look good around the SIO.

 

Any thought where to look next?

 

And how compatible are parts from the 65XE? I noticed the Antic has a different number between my dead 65XE (12296B) and 130XE (21698).

I'm thinking simple problem. You say the drive and SIO cable are good. Are you sure the drive is set to D1:?

[Rybags]

If that power supply is pumping that much juice, then it's probably the cause of all the problems.

[eeun]

I'm thinking simple problem. You say the drive and SIO cable are good. Are you sure the drive is set to D1:?

 

One of the first things I checked. Wish it was something that simple! The setup works fine if I swap in my 800XL for the 130XE, so that rules out SIO cable and drive.

 

@Rybags; Been too long since my 8-bit days, and I foolishly assumed that if the plug fits... Well, I know I've got an official 800XL PSU in the basement, so I'll dig that out and give it a try.

[eeun]

First up, I don't know where my brain was yesterday. Both power supplies I was using are indeed rated +5V. First, I read the volt-amp rating on the one, not the volts; and for the second one...any guesses? Yep, I looked at the bottom of the floppy drive power supply instead. But both were outputting too high a voltage. I did get that part right.

 

Dug out my 800XL supply, and it's giving me 5.46V. The 130XE will now only boot to the ROM/RAM test screen, with a black background instead of blue.

 

I think it's time to put it on the shelf for a bit. keep researching, and wait until my RAM sockets arrive and go at it fresh.

Edited March 7, 2011 by eeun

[sloopy]

First up, I don't know where my brain was yesterday. Both power supplies I was using are indeed rated +5V. First, I read the volt-amp rating on the one, not the volts; and for the second one...any guesses? Yep, I looked at the bottom of the floppy drive power supply instead. But both were outputting too high a voltage. I did get that part right.

 

Dug out my 800XL supply, and it's giving me 5.46V. The 130XE will now only boot to the ROM/RAM test screen, with a black background instead of blue.

 

I think it's time to put it on the shelf for a bit. keep researching, and wait until my RAM sockets arrive and go at it fresh.

 

bad ram is most common reason for direct boot to ram test... especially considering it is a 130XE, i would be willing to bet it has MT ram...

 

sloopy.