Synthchaser

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In the 4th installment of my Prophet 5 restoration video series we troubleshoot and repair a non-responsive Prophet 5.

[@davidvincent1911]

Hello and thank you for your very informative videos. I have a Prophet 5 rev 3.3 of which I completely changed the electronics with the exception of a few resistors because it presented the following problem which to this day is still not resolved: When I activate the PWM potentiometers while the PW is not even activated it has an action on my saw and pulses, slightly detuning them. Despite my investigations and an interest in manual service, I am seriously stuck and I really need someone to direct me on directions. If these symptoms mean anything to you it will be a big help to me. Thanks in advance.

[@jasonpike6652]

i have a quick question but first love your work very thorough. im just wondering about crystals and the tolerances as i have a yamaha psr 500 where the 9.4mhz crystal has corroded due to some sort of glue on it ,ive looked for one its a uc49 package but no luck i found a 9.375mhz i dont know if its a rare value or ive not looked in the best sites i did a google search but nothing any advice would be great

[@InterplainMusic]

What model is that desolder tool. Its just too easy.. Brilliant

[@jansensouza4180]

thanks a lot, it was helpfull

[@francescogoldoni7718]

Wondeful!

[@thayerhussey8888]

I have a Prophet 10 that I am planning to completely restore as you've done on the Prophet 5 in your videos. The Prophet 10 uses two of the exact same Pro5 sound module PCBs. The key beds are the same. I believe there may be differences in the Power Supply and CPU boards, and there is an additional interface PCB to integrate the two Pro5 PCBs. As in your restoration, I want to recap all boards, clean all pots and switches, and clean/rebush both key beds while installing several broken J-wires. I have a full Service Manual for the Prophet 10, plus a Diagnostic ROM chip set. If the Pro10 Power Supply Unit is different than the Pro5, can you add any needed additional components to your Pro5 Recap Kit to get the job done? Can you also supply Recap kits for all other Prophet 10 PCBs that are different from the Pro5? Also, can you provide the Brand and Model number of the Desoldering gun you use in your videos?

[@ingoodmusic]

Hi, can u share with a Service Manual, please?

[@jakebenbos]

Do you know if the memory test procedure is the same for Rev 3.3? On my Rev 3.3 unit (OS 10.5.0) when I jumper TP304 to the 5V TP, it just boots normally. There isn’t anything in the manual in the rev 3.3 manual addendum specific to the memory test that I can find. Thanks!

[@gazcbm]

Jakebenbos did you find anything? I have a 10.4 rev3.3 and would like to know the same. @synth chaser?

[@oliviertalouarn6258]

Will check if the jumper are easy to find with a Rev 3.0. But is it dangerous to perform tests before fixing old native PSU ? My Prophet stayed 3 day plugged, when warmed up, all is working except a non tuned sound and keyboard bad contacts. I m afraid of frying something. Thanks again for your knowledge share.

[@Synthchaser]

The power supply is always my first step in any restoration. Even if it's working, it's an important piece of preventative maintenance.

[@oliviertalouarn6258]

Looking at severals other synths vidéo made it obvious. Millivolts are pretty importants ... Restoring PSU is not an option ... and not so complex ... just soldering capacitors . Logic boards failures needs more knowledge, i m very impressed. Here in France there is less than a handful of competent guys. But with those video and your kit, a bunch of repair can be done "at home". Do you plan non US synths , as korg MS20 and others ? I know severals peoples in despair with those, and me too ... And there is not "numeric" in those, should be less complex than a prophet or a Memory moog

[@Synthchaser]

I do have some dead Roland, Korg and Yamahas here that I'll be repairing when time permits. Will post some video when I do.