From Kenny Balys Sent Thu, Aug 9th 2018, 22:16
From Kenny Balys Sent Thu, Aug 9th 2018, 22:16
Good tip, but do not be too quick to clip out chips on old Roland gear. I have, several times, seen people get too cowboy and conclude a chip is bad when its actually a cold solder joint / trace or board issue. This, often, is repaired by the new chip being freshly soldered in place. * (ahem... I was one of those cowboys) Basically don't replace or change anything at all on any early 80s Roland synth without first spot soldering everything and checking traces. This will likely fix at least half of all problems. I have personally worked on JP-6's, SH-101's, MC-202's, Juno-6's and 106's with this issue. Also, I wouldn't come down hard on the seller. This is something that is likely to happen with all of these units. Your's will give you years of service after it is repaired. I fully expect something to not be working whenever I get an old synth. Now I don't even power it on until its been opened, visually inspected and tightened. On 09.08.18 20:13 , Landon Balk wrote: > May be IC28 (I think??) the amplifier. per the schematic it ties into both > headphone out & main out. I had one be partially bad on my 202 when I > purchased it, to where the headphones only played in one ear, but the line > out worked fine. Bought one on ebay for $8, replaced & was all set. > https://www.ebay.com/itm/1-PC-M5218L-MIT-DUAL-OP-AMP-6000uV-OFFSET-MAX-7MHz-BAND-WIDTH-PSIP8/322552238135?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 > > here's a link to the one I bought. > > Of course open it up & check for any other obvious culprits too. Check that > voltages in/out of amp chip are proper, etc. > > On Thu, Aug 9, 2018 at 3:49 PM, Kenny Balys <xxxxx@xxxxxxxx.xxx > <mailto:xxxxx@xxxxxxxx.xxx>> wrote: > > > Is there audio from the headphone jack? > > Does wiggling the cable in the output make it work? > > Is the env / gate trigger configured appropriately? > > Is the scaling and tuning correct? > > Is it functionally the same on batteries as wall wart? > > Usual Suspects: > > - cold solder joint has failed - board trace has failed - output jack is > schmutzy and is loose from board > > > > On 09.08.18 17:57 , David Bivins wrote: > > Hi all, > > I just got an MC-202 that was shipped to me cross-country (USA). It was > well-packed and arrived in excellent condition. I had good communication with > the seller, so I have no reason to believe he misrepresented the instrument. > > It makes almost no sound. If I crank the gain on my mixer, I can faintly hear > the highest notes. I can definitely hear the gate (or some signal for > note-on). I've used batteries, the supplied PSU (Boss PSA); I've played the > chiclet keyboard and driven it from a 303 via CV/gate. I own and use a 101 > and many other synths, so I'm pretty sure I got the VCO/VCF/VCA/ENV correct. > I can put the audio cable into the output of my 303 and hear it just fine. > Same cable into the 202, just, as I said, the faintest sound. > > Note that it has a Kenton kit installed for control of pitch, gate, > portamento, and filter. > > I've contacted the seller, too, but I thought I'd tap into the analog hive > as well. > > Any ideas? > > Thanks! > > David > >