32K Expansion Unit stopped working

[mutantcamel1979]

Hi I bought this version of the TI99 32K Expansion several months ago and tried it today but it has stopped working

 

TI99/4A 32K Expansion /w 3d printed case | eBay

 

When I turned it on I was greeted with a black screen, noise and the red light kept flashing and it took several attempts for the computer to come on properly.

 

Tried a few 32K games and got the error 32k memory expansion required and the red light no longer comes on, not even for a moment to indicate it is loading the game.

 

Has the thing died?

 

I plugged it straight into the TI99 and have never plugged it through the speech synthesiser without a power supply as I know you can fry it that way.

 

Any help would be appreciated!

Edited September 9, 2022 by mutantcamel1979

[+jedimatt42]

You are in the wrong subforum, and should have posted in the top TI-99/4A forum. This subforum is meant to be about the stuff not for the 4A but loosely related by manufacturer or CPU family.

 

----

That said, this needs a 5V power supply plugged into the back. Too much voltage, and it would likely be damaged. No voltage and it may leach power from the 4A address bus, and 'seem to work'.

----

 

If more discussion is needed, I recommend moving the conversation to the correct forum.

 

(This thread has been moved to the correct place)

[mutantcamel1979]

**Update I sent it back for repair and it still does not work! I tried powering it using a 5V 2.1 x5.5mm Barrel Jack to USB lead, but it made no difference.**

 

Some games try to load up and I get a flickering red light still, the same as before.

 

I am at a loss of what is wrong and have ordered a replacement from elsewhere to see if that works!

 

To me it is strange how it worked before without a power supply.

 

Edited October 18, 2022 by mutantcamel1979

[HOME AUTOMATION]

Mine 'seems to work' without the power supply too.

 

...But then again, I recharge my own light bulbs!  ⚡⚡

 

[mutantcamel1979]

 I am confused on Ebay you can buy one without a power socket.

 

New Texas Instruments Computer TI99 4A 32K Sidecar Memory Expansion Card #729 | eBay

 

Wont this just do the same thing?

 

 

Edited October 18, 2022 by mutantcamel1979

[Stuart]

33 minutes ago, mutantcamel1979 said:

 I am confused on Ebay you can buy one without a power socket.

 

New Texas Instruments Computer TI99 4A 32K Sidecar Memory Expansion Card #729 | eBay

 

Wont this just do the same thing?

 

 

That one is set up to take power from the side port (the same way that the speech synthesiser does).

 

With the low power chips used on the card, they can often derive enough power to work just from the address bus lines. But best of course to use a proper power connection (external or from the side part) for reliability.

 

Have you tried cleaning the side port with a cotton bud and isoprop alcohol or similar?

 

Whereabouts in the UK are you?

 

 

[jrhodes]

1 hour ago, mutantcamel1979 said:

 I am confused on Ebay you can buy one without a power socket.

 

New Texas Instruments Computer TI99 4A 32K Sidecar Memory Expansion Card #729 | eBay

 

Wont this just do the same thing?

 

 

If you plan on using a TIPI later on, i would not order that. It does not have the pins to connect the TIPI board to it.

[mutantcamel1979]

I am from Yorkshire in the UK.

 

I just want a 32K that works, not too bothered about anything else at the moment.

 

 Tried another 5V adapter and the red light flickers like crazy and does not load anything up.

 

Yes I cleaned the contacts and they were fine. My Speech Synthesiser also works ok when plugged in.

 

Do you have to do something with the shielding inside the synthesiser so the 32K plugs into it or should it just slot into it. I was planning to try it that way with it plugged in naturally!

Edited October 18, 2022 by mutantcamel1979

[+Lee Stewart]

51 minutes ago, mutantcamel1979 said:

Do you have to do something with the shielding inside the synthesiser so the 32K plugs into it or should it just slot into it. I was planning to try it that way with it plugged in naturally!

 

The speech synthesizer does not pass the +5V through. It needs modification for that. Without modification, anything needing the +5V line should be ahead of it on the sideport.

 

...lee

[+jedimatt42]

"the red light flickered like crazy" makes me wonder if you can be more specific? When does it flicker?

 

It should flash on when an address in the memory expansion is accessed. 

 

It is not a power indicator. 

 

The closest thing to instructions for that board from the designer:

 

https://jedimatt42.com/4a/ti32kmem 

 

There is a blurb about use with speech synthesizer here: https://jedimatt42.com/4a/ti32kmem#speech-synthesizer

 

There is a jumper on the board as well that needs to agree with the chosen power source. Sometimes builders put a switch there instead... 

[mutantcamel1979]

The red light flashes constantly when it is trying to load a 32K game. As it does not load it just keeps flashing until I turn off the machine. 

 

I know when it worked it would flash for a second to load something. 

 

Thanks for the info about the speech synthesizer. 

 

It's a shame I don't have another 99 to test the unit on. 

Edited October 19, 2022 by mutantcamel1979

[+arcadeshopper]

- have you tried the memory test cartridge on a finalgrom or flashrom? 

- do you have extended basic?  If you load the cart and type CALL INIT the light should stay on..  if you type SIZE you should see the 32k memory. 

- seems like either a bad console or connection..  also likely you need external ps and to move that jumper clearly marked on the board to EXT if your console power isn't up to it

 

you are using 35+year old hardware.. the power supply in the console may or may not be 100%.. cap kits are available as are replacement boards..  flakey consoles are usually dirty connectors OR bad power.

 

Greg

[mutantcamel1979]

On 10/19/2022 at 2:30 PM, arcadeshopper said:

- have you tried the memory test cartridge on a finalgrom or flashrom? 

- do you have extended basic?  If you load the cart and type CALL INIT the light should stay on..  if you type SIZE you should see the 32k memory. 

- seems like either a bad console or connection..  also likely you need external ps and to move that jumper clearly marked on the board to EXT if your console power isn't up to it

 

you are using 35+year old hardware.. the power supply in the console may or may not be 100%.. cap kits are available as are replacement boards..  flakey consoles are usually dirty connectors OR bad power.

 

Greg

I tried the CALL INIT command in Extended Basic and got an illegal syntax error. I tried moving the jumper to Ext, but it made no difference, the light flickered constantly and the game did not load up.

 

However I have received another version of the 32K, smaller with no external power supply, when loading a game the light flickers all the time ....but it seems to work so far. However doing the Call Init followed by Size command in Extended Basic gave only 24488 bytes free of program space free. 

 

Is that correct? Should it not be 32K showing rather than 24K?

 

I do not have the memory test rom on my Final Grom to validate it is working correctly.

 

 

 

 

 

 

 

Edited October 23, 2022 by mutantcamel1979
missed important details off original

[+arcadeshopper]

6 minutes ago, mutantcamel1979 said:

I tried the CALL INIT command in Extended Basic basic and got an illegal syntax error. I tried moving the jumper to Ext, makes no difference and it just flickers constantly as before.

 

Tried another version of the 32K with no external power supply and the light flickers all the time on that too....but it seems to work and load the 32K games I tried. However doing the Call Init followed by Size command in Extended Basic on this one gives only 24488 bytes free of program space free. 

 

Is that correct? Should it not be 32K showing rather than 24K?

 

 

 

the size command should be 24k.. the rest is stack

https://www.arcadeshopper.com/wp/ti-99-4a-faq-extended-basic/

 

[mutantcamel1979]

I received the smaller version of the 32K Expansion with no power jack and that seems to work fine on my TI.

 

I tried using a multimeter to measure the voltage on the sidecar of the TI99. I got +5.10 and -5.12 volts which I assume is fine.

 

I am at a loss of why the original 32K does not like my TI!