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Issues with Rocktron Parchmate Bradshaw
Old 23rd July 2020
  #31
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Quote:
Originally Posted by Rick Dalton View Post
OK, just wondering, the OEM I looked at was 1145ma.
Ok so i've fiddled some more this evening,
I've used the new xicor EEPROM and powered only the 5 v rail with my bench supply.
The thing displayed OK on the display.
Now the thing atleast starts up correctly and displays "ROCKTRON PATCHMATE".

The strange thing Is that the C character Is backward and the R keeps glitching.
If i try to switch the loops everything works ok.
As soon as i twist on of the encoders the thing shuts down and the current falls to almost zero.
Old 23rd July 2020
  #32
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Rick Dalton's Avatar
Quote:
Originally Posted by emm853 View Post
Ok so i've fiddled some more this evening,
I've used the new xicor EEPROM and powered only the 5 v rail with my bench supply.
The thing displayed OK on the display.
Now the thing atleast starts up correctly and displays "ROCKTRON PATCHMATE".

The strange thing Is that the C character Is backward and the R keeps glitching.
If i try to switch the loops everything works ok.
As soon as i twist on of the encoders the thing shuts down and the current falls to almost zero.
Sounds like you're making some headway

I was looking at power supply's and it looks as this may be more like 2 Amps.
I'm sure they're allowing for phantom power.

https://www.fullcompass.com/prod/192...ocktron-pedals
Old 23rd July 2020
  #33
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Quote:
Originally Posted by Rick Dalton View Post
Sounds like you're making some headway

I was looking at power supply's and it looks as this may be more like 2 Amps.
I'm sure they're allowing for phantom power.

https://www.fullcompass.com/prod/192...ocktron-pedals
So if i power the 5v rails It uses only 250ma then falls if i try to switch between presets.
Old 23rd July 2020
  #34
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Quote:
Originally Posted by emm853 View Post
So if i power the 5v rails It uses only 250ma then falls if i try to switch between presets.
That fall could be cause from other circuitry kicking in, LED's etc,,
Old 30th July 2020
  #35
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Quote:
Originally Posted by Rick Dalton View Post
That fall could be cause from other circuitry kicking in, LED's etc,,
Hi Rick,

Finally some good news

i've replaced the original EPROM with a 28c64
Replaced the old latches with brand new Texas Instrument CD components ( CD74HC137E and CD74HC573E)

i then removed 2 ferrite chokes betwenn the +/- 15v rails isolating the 5 volt rail
and powered the thing on with my external PSU.

finally this thing works correctly (of course the Relays are not working) and writes the X2816CP correctly.

so the good news is that the ROM was not Damaged by the old PSU.

now i have to find the issue on the other power rails.

i think something is leaking (like you said before).

P.S at least i have the dumps of both ROM now.
Old 31st July 2020
  #36
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Rick Dalton's Avatar
Quote:
Originally Posted by emm853 View Post
Hi Rick,

Finally some good news

i've replaced the original EPROM with a 28c64
Replaced the old latches with brand new Texas Instrument CD components ( CD74HC137E and CD74HC573E)

i then removed 2 ferrite chokes betwenn the +/- 15v rails isolating the 5 volt rail
and powered the thing on with my external PSU.

finally this thing works correctly (of course the Relays are not working) and writes the X2816CP correctly.

so the good news is that the ROM was not Damaged by the old PSU.

now i have to find the issue on the other power rails.

i think something is leaking (like you said before).

P.S at least i have the dumps of both ROM now.
Alright Man! That's good to hear. I wonder on those relays, if they're like the original Bradshaw,,, they were gas filled? probably not, after Rocktron took over. Glad you let me know, been wondering.
EDIT, you can take a needle on a string and hold it over a relay to see if its got magnetic pull, and I know you know a meter will tell you if its getting voltage.
Old 31st July 2020
  #37
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Quote:
Originally Posted by Rick Dalton View Post
Alright Man! That's good to hear. I wonder on those relays, if they're like the original Bradshaw,,, they were gas filled? probably not, after Rocktron took over. Glad you let me know, been wondering.
EDIT, you can take a needle on a string and hold it over a relay to see if its got magnetic pull, and I know you know a meter will tell you if its getting voltage.
right now the relays are not powered so of course they don't work.

tomorrow i'l try to bridge those 2 vias ( without the emi suppression caps).

let's see.
Old 31st July 2020
  #38
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Rick Dalton's Avatar
Quote:
Originally Posted by emm853 View Post
right now the relays are not powered so of course they don't work.

tomorrow i'l try to bridge those 2 vias ( without the emi suppression caps).

let's see.
Were the ferrite chokes in bad shape? I didn't look like anything smoked did it? Maybe the varnish just aged and crapped.
Old 1st August 2020
  #39
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Quote:
Originally Posted by Rick Dalton View Post
Were the ferrite chokes in bad shape? I didn't look like anything smoked did it? Maybe the varnish just aged and crapped.
Hi Rick ,

so i've removed the EMI filters ( HERE ) highlighted in yellow.


Now the machine is powered by my bench psu (only 5V rails sono Relays) and works and saves fine.

if i resolder those filters back (even with external power) it starts glitching again.

i tried to remove the 7915/7815 but even without them the thing glitches as usual.

Without those 2 filters everything works fine.
Old 1st August 2020
  #40
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Rick Dalton's Avatar
Quote:
Originally Posted by emm853 View Post
Hi Rick ,

so i've removed the EMI filters ( HERE ) highlighted in yellow.


Now the machine is powered by my bench psu (only 5V rails sono Relays) and works and saves fine.

if i resolder those filters back (even with external power) it starts glitching again.

i tried to remove the 7915/7815 but even without them the thing glitches as usual.

Without those 2 filters everything works fine.
are the C27 and C29 good? or are they originals? and whats that component next to C27? cant see it.
Old 2nd August 2020
  #41
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Quote:
Originally Posted by Rick Dalton View Post
are the C27 and C29 good? or are they originals? and whats that component next to C27? cant see it.
C27 and cc29 are new Nichicon Caps.

next to c27 there's a 1n4007 diode (already replaced).
Old 2nd August 2020
  #42
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Quote:
Originally Posted by emm853 View Post
C27 and cc29 are new Nichicon Caps.

next to c27 there's a 1n4007 diode (already replaced).
emm853, have you noticed if the PCB has just one ground plane or is their an digital ground also?
Old 3rd August 2020
  #43
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Quote:
Originally Posted by Rick Dalton View Post
emm853, have you noticed if the PCB has just one ground plane or is their an digital ground also?
the only chip that has a DGND and AGND connected together is the PMI7528 DAC used to control the 2 hush IC
AGND and DGND are shorted together.
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