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Rockin' Kat

TI 99/4a: blank screen with PEB?

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Hi,

 

So I'm getting my computer room/office set up and I just got my TI 99/4a setup and now I've run into a strange issue. When I turn on my TI 99/4a with the PEB turned on, the screen flashes for a moment and then turns black. When I turn the TI 99/4a on without the PEB being on, I get the usual ready screen and can access basic or cartridges. the disk drive in the PEB spins the disk with the red ractivity light on for a moment when the computer is turned on.

 

I've tried cleaning out the connectors on the 99's expansion port and the PEB's connector with quick drying contact cleaner, which got a lot of grime out but hasn't change the function.

 

Anyone here know how this is supposed to work/know whats up? I've got a couple floppies that are supposed to be new with games and an auto loader on them as well as the disk manager 2 cartridge.

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Hi,

 

So I'm getting my computer room/office set up and I just got my TI 99/4a setup and now I've run into a strange issue. When I turn on my TI 99/4a with the PEB turned on, the screen flashes for a moment and then turns black. When I turn the TI 99/4a on without the PEB being on, I get the usual ready screen and can access basic or cartridges. the disk drive in the PEB spins the disk with the red ractivity light on for a moment when the computer is turned on.

 

I've tried cleaning out the connectors on the 99's expansion port and the PEB's connector with quick drying contact cleaner, which got a lot of grime out but hasn't change the function.

 

Anyone here know how this is supposed to work/know whats up? I've got a couple floppies that are supposed to be new with games and an auto loader on them as well as the disk manager 2 cartridge.

 

Okay, first things first, what cards are in the P-Box besides the Flex Card and the Disk Drive controller? Do you have a 32K memory expansion card? Do you have an RS-232 card? If so, pull the 32K card out. Then turn on the P-Box and computer, does that correct the issue? If not, turn off the computer, stick it back in and try all the other cards one by one figure out if there is a defective card. If it's a defective card, you'll know what to replace, if it's not a card get back to me.

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Good advice so far. It also looks like some of the signaling on the Flex Cable card is getting through to the PEB bus, as it is doing a fast poll of the Disk system. Since that is the first poll on the bus, the problem is most likely one of the other cards (as the disk controller and Flex Cable seem to be working). Not a guarantee, but a definite good place to start. One other note--sometimes a PEB slot gets worn contacts or gummy, so try the cards in another slot--it doesn't reall matter where in the PEB thery are, with the exception of the disk controller, and that only has to be at the end because of the cables, so you can stick it in the second-last slot too.

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The flex card is plugged into slot 1 on left.... disk controller was in slot 7 rather that slot 8... I've moved it over to 8 but that doesn't have any effect.

 

In slot 2 is a rs232 interface from Myarc Inc.

in slot 3 is a 32k x8 memory expansion from TI.

 

I removed both of these cards and tried turning everything on with no change in behavior.

 

I also tried cleaning all the slots and card edge connectors with quick drying contact cleaner. I didn't really get much grime on the cleaning sticks.

post-210-0-05410800-1398232938_thumb.jpg

Edited by Rockin' Kat

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There's a 12v and 5v line on the PEB power supply. Might be separately fused? If you have a voltmeter/DMM, you can check for both +5 and +12 at the power connector for the internal disk drive. Two ground wires on the 4-prong plug, meter from either of those to either of the other two and use the wire color code as a guide, black being ground. 12v will still spin the fan and the disk drive, maybe even the card access LEDs, but if the 5v supply failed, you'd get nothing beyond that.

 

I seem to recall a fuse inside the power supply cage in the PEB, can anyone refresh my memory of that?

 

Aside from that, I get more black screen startups from poor cartridge connections than anything. Presumably you are powering the PEB up first. I ran it all off a power bar, so there's not much need to wait very long between powering up PEB and then the console. All I could do in that instance was leave the PEB running, power console off, re-insert the cart to the left or right in the port, and cycle the console back on. Again, that's a cartridge/port issue, but might play a part somehow.

 

Wouldn't hurt to visit the edge card connector to the firehose and make sure it's not stressed. Try it without the speech module if that's connected, If this is a new-to-you system, you might even suspect a stress-related failure inside the console at the firehose connector or even a bumped/cracked external connector on one of the cards where they exit the back of the PEB.

 

PEBs are pretty robust in themselves, though I did need to repair one of mine once. Happily it was a simple fix, it had a bad rectum fire or something, lol. Failed cards might be another matter. All cards can be removed other than the interface card to eliminate those as mentioned above.

 

Substitute consoles to test further are pretty easy to come by if it looks like the problem lies in that direction. Shotgunning different cards and/or PEBs to track down the problem can get way too spendy, unless like me, you have a hoard of spares to toss at the problem.

 

-Ed

Edited by Ed in SoDak

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Well, I've tested both +12 and +5 volts on the floppy power connector with a multimeter and they read as they should.

 

I've tried both with and without the speech synthesizer in line. The TI works ok with cartridges, and was able to play with the call say command with the speech synthesizer.

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hrmm... well this is... interesting... apparently I've been plugging the PEB cable into the TI upside down... so... that edge isn't simply a handle... it keeps the plug level... hrmm... ok. Nothing to see here.... nothing to see here at all folks.

 

I'm clearly spoiled by non-reversible connectors.

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hrmm... well this is... interesting... apparently I've been plugging the PEB cable into the TI upside down... so... that edge isn't simply a handle... it keeps the plug level... hrmm... ok. Nothing to see here.... nothing to see here at all folks.

 

I'm clearly spoiled by non-reversible connectors.

LOL. A handle huh? :D

 

Glad you got it working RK :thumbsup:

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I really do appreciate the advice...

 

Anyway... now I've got some new "fun"

 

The Expanded Basic Auto loader on the two floppies I have crashes to a syntax error and trying the use the OLD command to load the individual game programs results in an I/O ERROR 50 message.

 

I'm using Disk Manager 2 to view the catalog disk and otherwise using the TI Extended Basic cartridge. All my other cartridges are games.

Edited by Rockin' Kat

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Depending on the loader--it might be trying to load Extended BASIC stuff, or it might be trying to load Assembly programs. I suspect the latter, as the error seems to fit. Look to see if your loader program has the commands CALL INIT :: CALL LOAD(DSK1.PROGNAME) somewhere in it, where progname will be the name of one of the files on your disk (the actual Assembly loader).

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OK, YLOAD is the assembly loader that is used to load the Assembly programs. LOAD is the XB program that starts everything. Each of the other programs on the disk is in Assembly--and will not load directly into Extended BASIC. You'll get the I/O Error 50.

 

From the looks of things, since only the first two selections are showing up in the menu, there is something wrong with the XB part of the loader. There may also be a problem with your expansion memory--as you need it to run any Assembly program. Since you do have a 32K card--the problem may also be with your card, probably in the low memory area, as that is where YLOAD gets loaded by the CALL INIT:: CALL LOAD("DSK1.YLOAD"). That should be loading to the low memory while the menu is being built, and if it fails there, either YLOAD isn't loading (possibly a corrupt file), or the memory it is trying to load into isn't there (Low memory on the 32K card) or possibly just partially functional. It is also remotely possible you have a bad Extended BASIC cartridge (or it has dirty contacts--try and clean them and the cartridge port too), as I have occasionally seen this problem with the cartridge (it is VERY rare though, so the other items are much more likely).

 

You might also want to move the 32K card into another PEB slot, just in case some of the contacts there have been oxidized or gone bad in the slot you're using. . .

 

Thank you for a perfect display of your problem with the video--it was a major assist when looking at the problem remotely! :)

Edited by Ksarul

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Can you show me whats on line 125? It say's syntax error, so I'm ASSUMING it's something that might just be mis-typed and easily fixed. Once that is done, you'll be able to save the program and run.

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Can you show me whats on line 125? It say's syntax error, so I'm ASSUMING it's something that might just be mis-typed and easily fixed. Once that is done, you'll be able to save the program and run.

 

Line 125 is listed later in the video at 2:50, It says:

 

125 CALL INIT :: CALL LOAD("DSK1.YLOAD")

 

post-210-0-34354500-1399002455_thumb.jpeg

 

I'm going to try moving the 32k card to a different slot tonight. I've already cleaned the cartridge ports, fire hose connections, and the slots in the PEB with the quick dry version of DeOxit. In the case of the TI, I had to clean the cartridge port and cartridges before I could even get it to work at all... I went through several cleaning sticks on it. After cleaning the cartridge port I just went and cleaned all the other card edge slots and connectors in the system. It turned cleaning sticks quite black at first.

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That's what I suspected--you are not successfully loading the Assembly loader (YLOAD). You may not be seeing the lower memory where it is supposed to load in the 32K card (most likely problem), which can be a result of the card slot it is in (you're checking that, which is good), or dirty contacts (which you've already addressed). The last possibility is that the portion of your Extended BASIC cartridge that initiates the load (the part storing the CALL INIT :: CALL LOAD("DSK1.YLOAD")) is defective. I have a lot of Extended BASIC carts floating around if it turns out to be there. Do you have access to another memory card? That would be another important check--or try to run the Diagnostics module or the CorComp PDM (if you have either of those) to test the card in system. You can also run the 32K Diagnostic program from the Mini Memory if you have that and the Diagnostics Disk.

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