From Brian Willoughby Sent Sun, May 26th 2019, 00:33
Bob seems way more knowledgable about the Synthex, so perhaps he=E2=80=99l= l 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=E2=80=99= re lucky, dislodging any oxidization might restore normal operations. = I=E2=80=99m not sure whether there=E2=80=99s an effective way to clean = the pins without damaging them, but perhaps some alcohol and a swab = wouldn=E2=80=99t 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=E2=80=99t 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 >=20 > 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=E2=80=99ve never looked inside a Synthex, so I don=E2=80=99t know = what=E2=80=99s involved. >>=20 >> Brian >>=20 >>=20 >> 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. >> >=20 >> > I suggest changing out those SRAMs to see if that fixes the = problem. >> >=20 >> > You may want to buy enough chips in case the patch ones fail later = on, >> > as they are the same type. >> >=20 >> > Sorry I am not able to respond in the same thread. Using a = browser to read >> > the messages. >> >=20 >> > Bob Grieb >> >=20 >> > On May 25, 2019, at 9:49 AM, Neil Dunn <xxxx.x.xxxx@xxxxx.xxx> = wrote: >> >> Hi folks >> >>=20 >> >> I'm hoping someone can offer some advice and help me repair my = Synthex sequencer which has a few issues. >> >>=20 >> >> 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. >> >>=20 >> >> 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 >> >>=20 >> >> Any advice is welcomed >> >=20 >>=20