TC 2290 issue with TC 0050

[Mimiouille]

HI, new on GroupDIY, coming from France and so sorry for my approximative use of english !

I've build a handmade remote TC0050 and that was working great with my 2290...
until the rig doesn't respond at any command (midi, switch or front keys) ; just keeping the last preset used
Now, when switching on the 2290, delay time is running until 1023ms and nothing else works
(as if learn key was always pressed) audio is OK with a 1023ms delay on...

I've used a standard jack on the 0050 so the sleeve was in contact with the lid of my midi pedal board
(the 0050 is screwed on the PB)
maybe a mistake, now I'm using an isolated jack with connectors separate from the lid but too late...

I've tried to fix it with an electronics engineer (with Schematics shared by gyraf) but unsuccessfully
If anyone have a good idea that would be great for me !

 

[gyraf]

Have you tried a full reset ( cant remember special no for that right now)?

edit: Set spec. 37 to 0, cycle power (generates err.13, all presets lost), set spec. 23 to 0 to acknowledge lost presets.

You have a spec. number list?

Jakob E.

 

[Mimiouille]

Thanks for your reply,

I have the spec number list but pressing spec key does nothing (all front keys does nothing)
I've change the prom (I've got a second V28.12 prom) and the ram too ; nothing better

I ask myself a question : what is L3 jumper made for ?
Maybe for a service test...

A good test (on a 2290 which works) would be to keep learn key pressed with one finger,
try to use another key and see if anything happen
If nothing happen, I can say it's as a short-circuit of learn key
(not front learn key because tested ok, but in Communication Interface or in CPU)

Mickaël

 

[gyraf]

If this happend' while experimenting with external remote stuff, could it maybe be Q402-403 (BC558, BC548) that feeds IC53 (DAC08)?

If Q402-403 or one of them is shorted, this might lock-up the control DAC? Check them?

Schematic p.11 - "Communication Interface Section"

Jakob E.

 

[Mimiouille]

I'm not sure about Q403
should be a BC548 in the part list and is a BC547B on the circuit board ; maybe both are ok for the job (few voltage differences)

the BC547B is NPN with pin order CBE and hFE between 200 and 450
mesure is infinite in this configuration and 320 in a NPN BCE configuration
Is it fried or my multimeter had lost is mind ?
Resistances between pins seems to be ok

A friend of me have a stock of new transistors
I will test a similar one
Q402 is not checked yet

Mickaël

 

[Mimiouille]

Q402-403 seem to be OK
To be sure, I have change them by new ones and the TC does not work better

R410 is tested OK

When i remove fuse F2 or F3 (not both) the TC can run with the same issue : just audio OK and a 1023 delay time ; no key enable
Is that mean D702 works great with half current ? or maybe the +15V section does not do the job and freeze front keys ?
(D702 does not exist in the part list ; physically there is 4 diodes)

Mickaël

 

[Mimiouille]

Power supply section is OK (+15VE, -15VE, +7, -7 and +5APEDAL)
so the problem is not there...
May be localized in COM , SCAN & REFRESH or CPU sections