OPL3LPT : OPL3 FM Synthesis on parallel port

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Re: OPL3LPT : OPL3 FM Synthesis on parallel port

Postby cde » 2019-7-08 @ 16:54

I would like to report my experience with the OPL3LPT: I have found it to be excellent, in particular using it with AdLib Tracker II (https://github.com/pdewacht/at2lpt/) is simply a joy, the sound is really good.

Unfortunately my OPL3LPT became defective, probably during the two weeks after I received it (I hadn't used during this time). Even though the PC was turned off, I had kept it powered on with a Samsung USB phone charger, and without any load (headphones or speakers) connected.

My initial hypothesis was that because of a lack of a load, a program that would try to access LPT1 (such as Windows 98 during installation?) would have caused sound output that reflected in the amplifier due to the lack of a load, and damaging it.

I contacted Serge at Serdaco (dreamblaster on this forum) who very quickly offered a replacement OPL3LPT and also provided me with the information needed to locate the source of the issue. After probing with a scope with OPL3TEST running, it appeared no clock signal was generated for the YMF262, hence the culprit would be either the 14.3 MHz OSC or the HC04.

Serge kindly sent me the necessary parts to try and perform a repair. As it turned out the problem was indeed with the HC04, and replacing it completely fixed the issue. This part is not hard at all to replace if you have some chipquik and flux for desoldering.

My advice to other OPL3LPT users would be as follows: make sure your 5V power source is clean (perhaps this phone charger was a counterfeit?) and be careful of ESD. Even with the plastic cover, the back of the PCB is still exposed, and so it is best to manipulate the OPL3LPT by the sides. Consider powering off the OPL3LPT when not in use (I have bought https://www.ebay.com/itm/-/201640973904 to switch off the power more easily).

So in conclusion I'm very satisfied not only with this great product but also with the prompt resolution of this problem and the great customer service by Serdaco! :-)
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Re: OPL3LPT : OPL3 FM Synthesis on parallel port

Postby matze79 » 2019-7-09 @ 14:07

My OPL3LPT is not everytime detected i need to several replug it/repower it to get it finally working in the Testprogram.

This is on Escom Blackmate 386SXL 33Mhz Notebook.

Anyone has similar issues ?
maybe this is also power supply issue, i power it from 5V Rail inside the Notebook.
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Re: OPL3LPT : OPL3 FM Synthesis on parallel port

Postby cde » 2019-7-09 @ 19:05

matze79 wrote:My OPL3LPT is not everytime detected i need to several replug it/repower it to get it finally working in the Testprogram.

This is on Escom Blackmate 386SXL 33Mhz Notebook.

Anyone has similar issues ?
maybe this is also power supply issue, i power it from 5V Rail inside the Notebook.


Initially I tried with the USB from my motherboard (KT7A) but it was too weak.

Have you tried with an external USB power? Such as a phone charger.
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Re: OPL3LPT : OPL3 FM Synthesis on parallel port

Postby mothergoose729 » 2019-7-09 @ 20:06

cde wrote:
matze79 wrote:My OPL3LPT is not everytime detected i need to several replug it/repower it to get it finally working in the Testprogram.

This is on Escom Blackmate 386SXL 33Mhz Notebook.

Anyone has similar issues ?
maybe this is also power supply issue, i power it from 5V Rail inside the Notebook.


Initially I tried with the USB from my motherboard (KT7A) but it was too weak.

Have you tried with an external USB power? Such as a phone charger.


Could you wire up USB power from a molex connector? That would turn and off with the PC and have plenty of juice.

EDIT: Like this https://www.amazon.com/Coolerguys-Molex ... B006JCHN08
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Re: OPL3LPT : OPL3 FM Synthesis on parallel port

Postby cde » 2019-7-10 @ 12:22

mothergoose729 wrote:
cde wrote:
matze79 wrote:My OPL3LPT is not everytime detected i need to several replug it/repower it to get it finally working in the Testprogram.

This is on Escom Blackmate 386SXL 33Mhz Notebook.

Anyone has similar issues ?
maybe this is also power supply issue, i power it from 5V Rail inside the Notebook.


Initially I tried with the USB from my motherboard (KT7A) but it was too weak.

Have you tried with an external USB power? Such as a phone charger.


Could you wire up USB power from a molex connector? That would turn and off with the PC and have plenty of juice.

EDIT: Like this https://www.amazon.com/Coolerguys-Molex ... B006JCHN08


That's a great idea that I didn't think of initially. I will certainly try that as the 5V from my PSU (Seasonic brand) is certainly of better quality that a phone charger.
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Re: OPL3LPT : OPL3 FM Synthesis on parallel port

Postby dreamblaster » 2019-7-10 @ 16:20

mothergoose729 wrote:Could you wire up USB power from a molex connector? That would turn and off with the PC and have plenty of juice.
EDIT: Like this https://www.amazon.com/Coolerguys-Molex ... B006JCHN08


That's a good idea !
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OPL2LPT, OPL3LPT, X2, S2, S2P, MCE2VGA, ... many projects !
Special vogons LPT bundle : https://www.serdashop.com/Parallel-port-retro-sound-bundle
Thanks for your support !
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Re: OPL3LPT : OPL3 FM Synthesis on parallel port

Postby matze79 » 2019-7-11 @ 11:14

Thats not possible, but i can use Step Down Converter from the 16-19V Input.
But.. OPL2LPT is always detected thats weird.
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