From lucidsound Sent Sun, May 26th 2019, 13:20
From lucidsound Sent Sun, May 26th 2019, 13:20
Are we even sure the Synthex should retain the sequencer data on power down? I've worked on at least two where this didn't happen. The clients weren't bothered so it was a non-issue. Lucid. -----Original Message----- From: Brian Willoughby Sent: Sunday, May 26, 2019 1:35 AM To: Neil Dunn Cc: Analog Heaven Subject: Re: [AH] Synthex sequencer fault Bob seems way more knowledgable about the Synthex, so perhaps he’ll have more specific recommendations. Meanwhile, if you can solder, then you probably have enough experience to pull a chip from a socket and reinsert it without bending any pins. Try that with the chips at 2N and 2O (maybe also 2L and 2M). If you’re lucky, dislodging any oxidization might restore normal operations. I’m not sure whether there’s an effective way to clean the pins without damaging them, but perhaps some alcohol and a swab wouldn’t hurt. I spent quite a while trying to diagnose and replace parts on my Ensoniq EPS keyboard scanner, only to find out in the end that removing the main chip and then reinstalling it in its socket was enough to get everything working. Sometimes, with age, oxidization builds up on the pins. As for replacement parts, a 1Kx4-bit (4Kbit) NVRAM chip is probably going to be hard to find these days. Make sure you know its bad, and then your best bet is probably NOS (but it might be unreasonably expensive, due to dwindling supply). I got caught in a similar situation trying to resurrect a memory cart for a Buchla Thunder, and couldn’t find a chip that was exact. I got lucky and found that there was a mechanical short draining the battery, and not a faulty chip. For a while, I was considering manufacturing a new board that would adapt a modern memory chip to the old equipment design. Brian On May 25, 2019, at 11:50 AM, Neil Dunn <xxxx.x.xxxx@xxxxx.xxx> wrote: > Thanks for chiming in Brian, i can confirm the battery is working well so > i will change the SRAM chips over but can you advise where i can obtain > these please? > I can solder well but i'm no tech so my terminology is lacking somewhat > when looking for parts > > On Sat, 25 May 2019 at 18:29, Brian Willoughby <xxxxxx@xxxxxxxxxxxx.xxx> > wrote: >> Before you change any chips, could it be a battery? >> I’ve never looked inside a Synthex, so I don’t know what’s involved. >> >> Brian >> >> >> On May 25, 2019, at 10:14 AM, Bob Grieb via analogue >> <xxxxxxxx@xxxxxxxxx.xxx> wrote: >> > Sequencer data is stored in battery backed RAM, starting at address >> > 0400h, >> > which is the start of the RAM2 chip select, so chips 2L and 2M. >> > >> > I suggest changing out those SRAMs to see if that fixes the problem. >> > >> > You may want to buy enough chips in case the patch ones fail later on, >> > as they are the same type. >> > >> > Sorry I am not able to respond in the same thread. Using a browser to >> > read >> > the messages. >> > >> > Bob Grieb >> > >> > On May 25, 2019, at 9:49 AM, Neil Dunn <xxxx.x.xxxx@xxxxx.xxx> wrote: >> >> Hi folks >> >> >> >> I'm hoping someone can offer some advice and help me repair my Synthex >> >> sequencer which has a few issues. >> >> >> >> The sequencer is acting very odd, it stores random note data on all >> >> for channels with some being very long indeed. >> >> Once deleted (which can sometimes take two or three efforts) i can >> >> record sequences but once i power down and back on again my programmed >> >> sequences are gone and the random note data has returned. >> >> >> >> For the record i've had this unit approx six years and it's always >> >> been like this, it's MK2 with JB Emonds midi kit installed >> >> >> >> Any advice is welcomed >> > >>