Reply 180 of 191, by cde
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! 😀