Search found 127 matches

by sadrew
05 Apr 2017, 19:29
Forum: Pedal Debugging & Troubleshooting Support
Topic: vintage EHX Electric Mistress very strange issue
Replies: 0
Views: 348

vintage EHX Electric Mistress very strange issue

Hi everybody I am having a very weird problem with my Electro Harmonix Electric Mistress (vintage SAD1024 version) The pedal is not working properly, only the clean guitar signal can be heard, with a slight distortion and lfo ticking in the background. If i disconnect the input jack and reconnect it...
by sadrew
21 Aug 2016, 10:01
Forum: Pedal Debugging & Troubleshooting Support
Topic: Electro Harmonix Polychours calibration procedure
Replies: 4
Views: 836

Re: Electro Harmonix Polychours calibration procedure

I have found the factory schematic for the MN3008 / MN3009 circuit

On the schematic there is also information on how to set the clock trimmer, which in fact is different from the older version
by sadrew
21 Aug 2016, 09:56
Forum: Pedal Debugging & Troubleshooting Support
Topic: Electro Harmonix Polychours calibration procedure
Replies: 4
Views: 836

Re: Electro Harmonix Polychours calibration procedure

thank you, but i believe that is the documentation for the older version, with sad1024 ics
by sadrew
20 Aug 2016, 18:20
Forum: Pedal Debugging & Troubleshooting Support
Topic: Electro Harmonix Polychours calibration procedure
Replies: 4
Views: 836

Electro Harmonix Polychours calibration procedure

Hi everybody I just got this stereo polychorus included in a lot of old pedals, it's the big box reissue (MN3008 bbd chip) it works but someone clearly messed up with the internal trimpots, with the feedback control past half way it starts oscillating and with certain settings of the width control t...
by sadrew
02 Apr 2016, 11:16
Forum: Pedal Debugging & Troubleshooting Support
Topic: Dynacord VRS23 BBD delay - longest delay time preset dead
Replies: 1
Views: 444

Dynacord VRS23 BBD delay - longest delay time preset dead

Hi everybody . Not really a stompbox here but really a nice unit. I have been scratching my head a lot lately unfortunately my Dynacord VRS 23 delay has developed a problem The longest one of the four delay time settings doesn't produce effect sound anymore Other three shorter delay settings operate...
by sadrew
07 Dec 2015, 09:35
Forum: Modern Stompbox Effects (1975 - ...)
Topic: MXR 129 pitch transposer
Replies: 8
Views: 6515

Re: MXR 129 pitch transposer

unfortunately this is a tad more complex than a fuzzface, so I don't fully understand this circuit :oops: but hopefully i will succeed in troubleshooting the noise at least the trimpots are old metal type and they have been soldered ! you can't really turn them anymore I hope the machine will stay i...
by sadrew
06 Dec 2015, 21:38
Forum: Modern Stompbox Effects (1975 - ...)
Topic: MXR 129 pitch transposer
Replies: 8
Views: 6515

Re: MXR 129 pitch transposer

that is some wise advice mr Hendrik ! Indeed I purchased the schematic

Then.... where can i get the calibration information ? :)

Thanks,
Giacomo
by sadrew
06 Dec 2015, 18:06
Forum: Modern Stompbox Effects (1975 - ...)
Topic: MXR 129 pitch transposer
Replies: 8
Views: 6515

MXR 129 pitch transposer

I am trying to repair a pitch shifting rack unit from MXR, the model is M-129 pitch transposer I am desperately trying to find the schematics I am trying to tackle some weird distortion that is happening in the pitch shift section but I can't really operate without a schematic, all the ics have been...
by sadrew
25 Feb 2015, 12:49
Forum: Pedal Debugging & Troubleshooting Support
Topic: mxr pitch transposer repair question
Replies: 4
Views: 894

Re: mxr pitch transposer repair question

very hard to address the problem without a schematic

have you tried trace the signal path with an audio probe ?
by sadrew
24 Feb 2015, 11:53
Forum: Pedal Debugging & Troubleshooting Support
Topic: mxr pitch transposer repair question
Replies: 4
Views: 894

Re: mxr pitch transposer repair question

that's a complex unit and no schematics around it seems

power supply checks ok ?
by sadrew
24 Feb 2015, 11:50
Forum: Pedal Debugging & Troubleshooting Support
Topic: Moog MF-102 problem
Replies: 0
Views: 490

Moog MF-102 problem

I have this very nice ring modulator pedal by moog and the bypass function stopped working The pedal is always ON, footswitch don't make a difference, and the "BYPASS" and "LEVEL" LEDs don't light up Unfortunately there are no schematic available, although I have found on the for...
by sadrew
11 Feb 2015, 07:22
Forum: Pedal Debugging & Troubleshooting Support
Topic: weird power supply latch up problem
Replies: 0
Views: 360

weird power supply latch up problem

i am repairing an old electro harmonix mistress flanger. i have managed to make it work, but the power supply still has some problem if i disconnect power from the pedal, when i plug in again it doesn't work anymore. if i touch 2N4354 transistor in the psu section with multimeter, the pedal starts w...
by sadrew
10 Dec 2014, 17:21
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: MXR - Flanger/Doubler ( M-126 ) [schematic]
Replies: 24
Views: 27414

Re: MXR - Flanger/Doubler ( M-126 ) [schematic]

i have one of this great sounding delays and unfortunately it has developed a noise issue i can hear the effect flanging but there is a loud motorboating noise too the noise disappears in bypass or when the mix knob is in dry position i already recapped the unit with fresh electrolytics but the nois...
by sadrew
02 Dec 2014, 10:48
Forum: Modern Stompbox Effects (1975 - ...)
Topic: TC Electronics - Stereo Chorus Flanger [pcb+layout] [schematic]
Replies: 197
Views: 146826

Re: TCE - Stereo Chorus Flanger [pcb+layout] YUP! [schematic]

i have bought an original SCF to repair

i was wondering how did you find out IC values

in my unit they are sanded down
by sadrew
01 Jun 2014, 15:40
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Roland - AD-50 ( Double Beat ) [schematic]
Replies: 78
Views: 54715

Re: Roland - AD-50 ( Double Beat ) [schematic]

i would suggest to isolate the fuzz section and see if still has the problem

at least you know if the problem is in the fuzz or in the wah circuit and narrow your search

main suspect also might be out of range power supply voltage or cabling problem

let me know if you need more help
by sadrew
12 Apr 2014, 18:53
Forum: Modern Stompbox Effects (1975 - ...)
Topic: TC Electronics - Stereo Chorus Flanger [pcb+layout] [schematic]
Replies: 197
Views: 146826

Re: TCE - Stereo Chorus Flanger [pcb+layout] YUP! [schematic]

amazing job you guys done on this!

should we organize a forum group buy for pcbs?

then, a clone of the 1210 would be amazing. anyone can share pcb pictures? please please
by sadrew
07 Jan 2014, 00:24
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: EHX - Echoflanger [schematic]
Replies: 197
Views: 154659

Re: EH Echoflanger [schematic]

actually it was turning continuously ( stop pin lost?? )

then i opened it and turned the board and found it was split in two parts

if a replacement is impossible to find i'll try to use a normal rotary
by sadrew
06 Jan 2014, 15:33
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: EHX - Echoflanger [schematic]
Replies: 197
Views: 154659

Re: EH Echoflanger [schematic]

I just scored an original echo flanger for a bargain. It's not working at the moment but I hope to fix it. For starters The rotary switch is broken and needs replacement. The common lorlin type won't fit there, actually the switch is a strange type i've never seen before. Here you have a picture to ...