Sound Chip AY-3-8912 vs. AY-3-8912A

[vtk]

hello all,

 

i was having a look around ebay for a replacement AY-3-8912 sound chip for the vectrex, and noticed on ebay that the AY-3-8912A revision of the chip is more readily available, and very cheap in price compared to the earlier AY-3-8912 revision

 

but i read somewhere that the AY-3-8912A revision of the chip may not work in the vectrex (perhaps somebody here could confirm?)

 

i found the pinouts for the AY-3-8912, and the AY-3-8912A revision, and it 'appears' that the only difference is with PIN 2, see diagram below:

 

 

 

i tried to find some information online regarding PIN 2, and noticed elsewhere that some people were discussing about lifting PIN 2 so that it is not used/connected, but also other people were suggesting to connect it to +5v or to GROUND .... but anyway there was not really a final solution or outcome/resolution to the discussion

 

i found a 'data manual' online regarding the AY-3-8912, link here:

http://f.rdw.se/AY-3-8910-datasheet.pdf

and i notice on the 13th page down, it states:

"The Test Pin is for GI (General Instruments Company) test purposes only, and should be left open (and not used as tie points)"

 

hmm, so does anyone have any advice regarding this.. could the AY-3-8912A work in the vectrex, or must we stick with the AY-3-8912?

Edited December 31, 2015 by vtek

[fiddlepaddle]

If it's cheap, I would try it. Based on your research, it doesn't look like you would damage anything.

[R.Cade]

The schematics don't show any connection to pin 2, so you should be fine. You can verify this first with a meter, or else lift the pin if it worries you. I doubt it would make any difference either way. It should work fine. The chip is a drop-in replacement.

[Tickled_Pink]

hello all,

 

i was having a look around ebay for a replacement AY-3-8912 sound chip for the vectrex, and noticed on ebay that the AY-3-8912A revision of the chip is more readily available, and very cheap in price compared to the earlier AY-3-8912 revision

 

but i read somewhere that the AY-3-8912A revision of the chip may not work in the vectrex (perhaps somebody here could confirm?)

 

i found the pinouts for the AY-3-8912, and the AY-3-8912A revision, and it 'appears' that the only difference is with PIN 2, see diagram below:

 

 

 

i tried to find some information online regarding PIN 2, and noticed elsewhere that some people were discussing about lifting PIN 2 so that it is not used/connected, but also other people were suggesting to connect it to +5v or to GROUND .... but anyway there was not really a final solution or outcome/resolution to the discussion

 

i found a 'data manual' online regarding the AY-3-8912, link here:

http://f.rdw.se/AY-3-8910-datasheet.pdf

and i notice on the 13th page down, it states:

"The Test Pin is for GI (General Instruments Company) test purposes only, and should be left open (and not used as tie points)"

 

hmm, so does anyone have any advice regarding this.. could the AY-3-8912A work in the vectrex, or must we stick with the AY-3-8912?

 

If you want to try it, send me a couple of quid and I'll send you one. I'd like to know as well but mine sounds terminal enough as it is. The only difference from the GI part used in the Vectrex is that the ones I have were manufactured by Microchip.

[vtk]

hello guys, yes i agree i think because the AY-3-8912A is very cheap on ebay, it is worth trying this with the vectrex

 

so i will purchase one of these now:

 

http://www.ebay.co.uk/itm/252201432390

http://www.ebay.co.uk/itm/291496696829

http://www.ebay.co.uk/itm/171819960455

 

when it arrives and i try it, i will report back here to let you know if it works out ok

Edited December 31, 2015 by vtek

[juice2839]

hello all,

 

i was having a look around ebay for a replacement AY-3-8912 sound chip for the vectrex, and noticed on ebay that the AY-3-8912A revision of the chip is more readily available, and very cheap in price compared to the earlier AY-3-8912 revision

 

but i read somewhere that the AY-3-8912A revision of the chip may not work in the vectrex (perhaps somebody here could confirm?)

 

i found the pinouts for the AY-3-8912, and the AY-3-8912A revision, and it 'appears' that the only difference is with PIN 2, see diagram below:

 

 

 

i tried to find some information online regarding PIN 2, and noticed elsewhere that some people were discussing about lifting PIN 2 so that it is not used/connected, but also other people were suggesting to connect it to +5v or to GROUND .... but anyway there was not really a final solution or outcome/resolution to the discussion

 

i found a 'data manual' online regarding the AY-3-8912, link here:

http://f.rdw.se/AY-3-8910-datasheet.pdf

and i notice on the 13th page down, it states:

"The Test Pin is for GI (General Instruments Company) test purposes only, and should be left open (and not used as tie points)"

 

hmm, so does anyone have any advice regarding this.. could the AY-3-8912A work in the vectrex, or must we stick with the AY-3-8912?

 

The difference between the 8912A and 8912 is the A does not have internal pull up resistors on the output port. I'm not sure if this makes a difference with the vectrex.

Edited January 1, 2016 by juice2839

[vtk]

Vectrex Friends,

 

The test results are here .....

 

and the news is good... i put the AY-3-8912A sound chip (mine is the Taiwan Motorola 'microchip' version, pictured below) into my Hong Kong model vectrex, and tried it out with some various sound/music tests; i used the TEST CART sound test, and also had a go of the game 'Minestorm' , and then finally tried the game 'Thrust' (which plays some Rob Hubbard converted chip music with lots of varying effects/sounds/noise playing).

 

I encountered no problems. Everything sounded exactly the same as when using my regular original GI (General Instruments) AY-3-8912 sound chip (pictured below).

 

one more thing... i remember reading that the vectrex sound chip is also used regarding the joystick controllers (Input/Output), so i also tested (using the TEST CART) both of the joystick ports, with 2 controllers plugged in at the same time. there were no problems here. both of the controllers functioned as normal/correctly.

 

so that's good news then, you can just buy the cheaper more available AY-3-8912A sound chip for your vectrex (well, at least it's ok with the Hong Kong model vectrex). Hopefully it will also be ok for the other vectrex model versions (such as the 'made in taiwan' vectrex models, etc).

 

.. and that's that.

 

(unless anyone wants me to do any more tests...? if so, let me know) .....

 

 

[Mayhem]

Great news

 

Now, how easy is it to replace the chip in a Vectrex? Never had one open you know...

[vtk]

Now, how easy is it to replace the chip in a Vectrex? Never had one open you know...

 

if you dont like the idea of removing a circuit board from the vectrex, most of the (socketed) chips can be removed ok without needing to dis-assemble the vectrex parts

 

the AY-3-8912 soundchip is a little tricky to remove, but it's possible, and i can do it ok now as i did it a few times and now it's easy (a little tricky the first time if not had practice)

 

i just use a set of tweezers, which i bend the legs at the end so that it can be used to grip the chip, so i can pull them off (see pics)

 

(but perhaps a more professional tool to remove chips can be purchased from eg. ebay)

 

Edited January 6, 2016 by vtek

[carlsson]

On an related note, I've seen several really cheap AY-3-8912 chips on eBay, mostly from Chinese or Hong Kong vendors, that are pictured with what looks like date codes 0048, 0613, 0618, 0934, 0808207 (?). Some are marked GI, some are marked Microchip. Is it a correct assumption those have been refurbished and repainted - possibly even fake, although AY-3-8912 doesn't seem valuable to fake and sell for $1.50 - $3.00 each? I've understood that GI transferred production to Microchip in 1987, so any chips from the very late 80's or perhaps early 90's likely are from Microchip or any second source, not GI themselves.

 

The price difference is not that much, so I could buy slightly older dated chips, but as the supply seems to be plentiful and in case of faking it seems strange to paint a relatively new date code, it got me wondering. One probably wants to test a such chip in some inexpensive tester before plugging into a valuable system.