Rodgers Providence 900

[HarryA122/45]

Anyone have experience with this model? Just got a nice 3m lighted dk organ with 7 speaker cabinets (utility). It does not work and I believe there to be a problem with the CPU or a component on the CPU board. When trying to turn on organ, the lights come on for about 2 seconds then go off. There is a switch on the main power supply which forces the organ to stay on by apparently shorting out the automatic turn off circuit. It seems that voltages are all correct coming from the voltage regulator boards. The fuse for the 5V blows (4A) but not immediately. In my tracing things out so far it appears that the 5V is only used on the CPU board and one other area, probably to do with reading the various states of knobs, keys, couplers, etc. Rodgers apparently is very closed mouth about sharing any service info unless you go thru an authorized service rep. I am trying to do that, but slow going so far. Talked with Rodgers service guy in Hillsboro yesterday and he said that the CPU's are still available.

Maybe someone else has some suggestions so bring this back to life!

Thanks guys.

Harry

[toodles]

I have had no personal experience, but this was one of the first MICASKO organs Rodgers produced--Microprocessor Analog Serial Keyed Organ, and what I have heard is they are trouble prone.

I've actually had good luck getting service manuals directly from the factory but this was a few years ago--maybe they've changed their policy. They generally provide a pdf of scanned manuals for these older models, and they are sometimes hard to read. Since the files are large, you would likely need to use a file drop-box service to get it.

[mr.horton]

Regarding service manuals from Rodgers:
They provide them (email pdf) free of charge if they have it and the one you want is one of the "LTG" type.
LTG would probably include all the analog organs, is my guess.
When I asked for a service manual for an organ that uses PDI (digital) technology, manufactured in 1992 I got turned down since I am not an authorized service rep.

[indianajo]

You may be in luck if the organ is first generation microprocessor. The second and third generation Intel parts are still available. 8008 generation is iffy.
I would take a Hall effect current probe and try to trace where the 5V current is going. Then replace that part. You may replace the fuse with a 4.7 ohm 10 W resistor or something while you are tracing.
To find the 5 v PS pins of the various IC's, datasheets should be available on datasheetcatalog.com. I checked the 8255 IC last year, Newark.com was stocking them. However, at this age my usual suspect for shorts is the electrolytic bypass capacitors on the boards. In those days, a lot of **** ceramic bypass caps were sold; if Rodgers incoming inspection wasn't particularly vicious one of those could also be a problem.
Good luck.

[arie v]

Hi,

This model I think is a Mikasco "B" series organ, which means that the console computer part of the organ should be relatively reliable. It was the early Mikasco series built from 1980 - '81 that were problem prone, and the factory had trouble figuring out what was wrong. By the mid 80s, Rodgers had re-designed the CPU board, which was part of a repair kit if the original CPU went down. I don't know if they would still have any of those boards available or not.

My guess is they might still have some of the later Mikacso CPUs on the shelf, especially if they say they do.

You may want to check to see if the fuse is the proper type. I have come across a number of folks who put in wrong value fuses, as well as wrong type, i.e. put in fast blo instead of slo-blo. You may also want to see if any ICs are running hot.

Typically if a small resistor or small cap. are shorting, they will burn up, and become open circuit. May want to check, that there is no object such as a paper clip, hair pin, etc. that is in a position to cause a partial short.

Good luck in trying to sort this out.

AV