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Thread Starter


Joined Oct 18, 2004
I am trying to duplicate a circuit and cannot find any information on the folowing parts.

An IC labled HT28831 9138G

A transistor labled TOA 2003 80C810

A transistor (i think) labled 9E-P126 (this is a small square box like IC with leads out the top and bottom.

This circuit is a sound module. I have searched the NTE and National Semiconductor Sites. Can anyone direct me to, or provide information on these parts?

Thanks in advance for any help
73 de Frank


Joined Oct 30, 2004

I can't guarantee it but i'm fairly certain that the IC "HT28831 9138G"
is a Holtek HT2883i which as far as i am aware is a sound generator chip and i suspect it is no longer in production by that manufacturer. From the breif searches i've done, it looks like it went out of manufacture around 1993.

The code on the end 9138 with most IC's is usually a date code from it's time of manufacture being made in 1991 on week 38

I don't have a great deal of time and resources at my disposal right now but if i think on i'll try and find out some more info and reply here.

I know Holtek sold a lot of their discontinued product designs to other manufacturers, so there is a good chance an equivalent is still in production.

Also i think Maplin electronics some years ago sold some of the Holtek HT28xx series of sound generator chips.

If you could let me know if sound like i'm on the right track i'll try and see what else i can find out, or am i totally barking up the wrong tree with this one?

Thread Starter


Joined Oct 18, 2004
Hi Maxx,
Yes this is in a sound circuit for duplicating a old diesel engine sound. From start up to idle, then faster running. It is an old circuit, I am not sure of the actual vintage.
Thanks for your help.

Boy oh boy what do i do now? :blink: