OBERHEIM SYNTH

Read through some other google links
do you think it could possibly be the photocoupler (pc900)
I will also start testing the regulator, since that
is what some have claimed to cause them problems. It's not
the power supply and all solder points and resistors look good...

--- In oberheim@yahoogroups.com, "cyllall" <cyllall@...> wrote:
>
> I'm looking at some pictures of a Cyclone I found online as I don't have any Perf/x stuff.
> 
> Check that all the legs in any socketed chips are actually in the socket. It is possible when putting a chip in, to bend the legs back on themselves in a "U" shape and it looks like they are in and they're not.
> There may be something wrong with your display showing 3 instead of 8.
> You can check for cracked solder or a short circuit by the display/resistors and underneath.
> This could be a power supply problem.
> You need to check the +5v and GND test points on the board.
> If you clip a crocodile clip to the regulator(as a heatsink) and it then takes longer to go funny then it could be the regulator.
> Make sure your power adapter is the correct voltage and unless it's the same mah rating as the original(or is the original) it should be a regulated/switched mode supply, so as not force too much current in.
> I would take the battery out for now as it could hold corrupted data in the RAM.
> Wait a few minutes and do a hard reset.
> 
> 
> 
> --- In oberheim@yahoogroups.com, "sokkerkid10101" <sokkerkid10101@> wrote:
> >
> > narfman96:
> > No nothing seems to be getting too hot but that seems like a very logical possibility and would explain why there is a delay for it reverting to a state of 0 ram, maybe the bad component is dealing with the ram
> > 
> > Martin:
> > The original battery was a DL2032, I tore that out and have in it now a CR2032. The original ram (8k one)is# made by hyuandai, I replaced it with a 32k of HM62256LP-10.
> > 
> > One thing to note is that when the version displays on startup, it says 3.3, although the manual says it should be at least 3.8
> > 
> > Yes the CPU (and the ROM for that matter) both appear to be in correctly
> > 
> > Yes there is only one ram chip
> > 
> > And yes I have access to a voltmeter (and one of those displays that show current and stuff-i know I sound like an idiot, I can't remember the name of them right now) I am not keen on circuitry however
> > 
> > 
> > Thank you
> > 
> > --- In oberheim@yahoogroups.com, "narfman96" <narfman96@> wrote:
> > >
> > > This problem sounds like a component is overheating and shutting down. A capacitor could be leaking to ground. Have a tech look at the power circuit and then the cpu and the rest of the digital section. Is anything getting warm or hot? 
> > > Fran
> > > --- In oberheim@yahoogroups.com, Martin Ator <cyllall@> wrote:
> > > >
> > > > Hi,
> > > > What type of battery is it? CR2032?
> > > > What is the part number of the original RAM, is it something like this on the 
> > > > end ******-15L
> > > > Have you identified the CPU, is it in a socket, is there only one RAM chip, have 
> > > > you got a voltmeter?
> > > > 
> > > > Martin
> > > > 
> > > > 
> > > > 
> > > > 
> > > > ________________________________
> > > > From: sokkerkid10101 <sokkerkid10101@>
> > > > To: oberheim@yahoogroups.com
> > > > Sent: Sat, 22 January, 2011 12:17:01
> > > > Subject: [oberheim] Re: Oberheim Perf/x Drummer problem
> > > > 
> > > >    
> > > > Thank you for the reply and info about the battery
> > > > 
> > > > I put a 32k ram chip in there but the problem still persists. However I believe 
> > > > the problem is due to something with the RAM since I get the same messages when 
> > > > there is no RAM chip in it; except it takes a few moments to occur when there is 
> > > > a chip in it. 
> > > > 
> > > > 
> > > > Any other help would be appreciated, I can make a video if needed. Also 
> > > > considering taking it to a pro...
> > > > 
> > > > --- In oberheim@yahoogroups.com, "Steve" <steve@> wrote:
> > > > >
> > > > > The battery keeps the data in the RAM alive.  Without it, it would revert back 
> > > > >to factory
> > > > > settings when you shut off the power.  Today we would use Flash memory for 
> > > > >this, but battery backed RAM was one of the better options back then.
> > > > > 
> > > > > As far as curing what ills your drummer, I can only suggest reseating anything 
> > > > >that is socketed, in case oxidation is making a bad connection somewhere.
> > > > > 
> > > > > --> Steve
> > > > > 
> > > > > --- In oberheim@yahoogroups.com, "sokkerkid10101" <sokkerkid10101@> wrote:
> > > > > >
> > > > > > Hey all, first of all- hi
> > > > > > I was running out of options until I found this wonderful group!
> > > > > > 
> > > > > > Secondly,
> > > > > > I just purchased an oberheim drummer off ebay and it started giving me 
> > > > >problems immediately. The issue is that, if I let it sit and rest for a bit, it 
> > > > >starts up fine and works great, until after about 1-3 minutes when all of the 
> > > > >function become inaccessible. AKA it shows "0" for preset, and it is 
> > > > >unchangeable, as well as all other functions show "oF" and I cannot change it. 
> > > > >This will happen immediately if I just switch it from on to off.
> > > > > > 
> > > > > > I have it opened up here (got scared that I had destroyed it on one or two 
> > > > >occasions while playing with the ram and eprom). I am trying a new battery but i 
> > > > >don't have my soldering iron here at school so it is just sitting between the 
> > > > >tabs.
> > > > > > 
> > > > > > what does the battery do btw?
> > > > > > 
> > > > > > And I have a new 32K X 8 ram on its way. 
> > > > > > 
> > > > > > Any other suggestions?
> > > > > > 
> > > > > > Thank you!
> > > > > >
> > > > >
> > > >
> > >
> >
>