Search found 59 matches

by pmkipp
22 Feb 2020, 18:26
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro EP3 T70-T2 Bias Oscillator Question [schematic]
Replies: 5
Views: 1454

Re: Maestro EP3 T70-T2 Bias Oscillator Question [schematic]

I got the preamp working, so the signal made the record and playback heads. Not it only does a single repeat (the initial playback). I checked everything in what I assume is the repeat section (upper left of schematic). The 35uf filtering cap to ground was dead, so replaced that. But the other elect...
by pmkipp
17 Jan 2020, 20:09
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro EP3 T70-T2 Bias Oscillator Question [schematic]
Replies: 5
Views: 1454

Re: Maestro EP3 T70-T2 Bias Oscillator Question [schematic]

AC voltage coming out of the T70T2 is 28 volts at pin 5 and 120 volts at pin 4. Resistance at erase head is 40ohms and at the record head is 70 ohms. Playback jack is not shorted. The 28 volts go through a trimpot on the way to the record head, but it has to be all the way off to let the whole 28 vo...
by pmkipp
17 Jan 2020, 02:10
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro EP3 T70-T2 Bias Oscillator Question [schematic]
Replies: 5
Views: 1454

Re: Maestro EP3 T70-T2 Bias Oscillator Question [schematic]

Thanks - is the voltage at 1 and 3 also AC, or is it DC?
by pmkipp
15 Jan 2020, 18:48
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro EP3 T70-T2 Bias Oscillator Question [schematic]
Replies: 5
Views: 1454

Maestro EP3 T70-T2 Bias Oscillator Question [schematic]

I have been rebuilding an old EP3 and have hit a snag, mostly from the "where do I find this?" corner. Someone before me had wired in a new power cable and must have done it backwards and blown both bridge rectifiers so nothing worked at all. Replaced the rectifier for the solenoid/shut off switch a...
by pmkipp
28 Aug 2019, 19:44
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro PSFS-2 Footswitch Design?
Replies: 3
Views: 2940

Re: Maestro PSFS-2 Footswitch Design?

Update - there was actually a busted switch in my build. Replaced it, now it works perfectly - used with all the onboard rockers in OFF position. Little pop when turned on or off, so need to figure that out...
by pmkipp
28 Aug 2019, 18:01
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro PSFS-2 Footswitch Design?
Replies: 3
Views: 2940

Re: Maestro PSFS-2 Footswitch Design?

So, I did figure this out. But it is a pain to build, mostly because of the 6 wire connector required and having to build the plug from scratch. It works fine with my PS-1A - the Blue (Slow) switch has to be on.
by pmkipp
06 Sep 2018, 15:12
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Real or Fake Reticon SAD1024 Chips?
Replies: 9
Views: 4865

Re: Real or Fake Reticon SAD1024 Chips?

I came upon a working '70's Ross flanger with the same Reticon chip (socketed) and was able to test all these purple chips and they all worked perfectly. The power input section to the Memory Man was shot and was bleeding voltage. I rebuilt it and now there is a cool 14.5v going into the circuit and...
by pmkipp
10 Sep 2017, 14:34
Forum: Pimp-My-Cheap-Pedal
Topic: How to install an LED in a Proco Brat
Replies: 1
Views: 2297

How to install an LED in a Proco Brat

Have seen some old posts on this. Twas not a popular pedal, but I think I figured it out. This works perfectly, and with the previously suggested clipping upgrades it is a killer distortion pedal. Unfortunately, I have not been able to solve the FET switching noise. As noted, there is a place on the...
by pmkipp
10 Sep 2017, 13:59
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Tech 21 GT2 Pops when turned OFF!
Replies: 1
Views: 854

Re: Tech 21 GT2 Pops when turned OFF! With Solution (Mostly.

This has not had many views (it is a pretty unusual problem), but just in case anyone is interested - There is a 47uf electrolytic resistor just off one leg of the switch that is NOT on the schematic. When I put a 1meg resistor from the ground of the cap to the ground on the input jack almost all of...
by pmkipp
10 Sep 2017, 13:41
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Real or Fake Reticon SAD1024 Chips?
Replies: 9
Views: 4865

Re: Real or Fake Reticon SAD1024 Chips?

Well - seems the problem may be with the chips, unless someone has another suggestion to check. Before I got this, when plugged in there was up to 22 volts going to the 1024 chips. The main problem in the power section was too much power coming out of the transformer (not the end of the world) and a...
by pmkipp
08 Sep 2017, 00:26
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Real or Fake Reticon SAD1024 Chips?
Replies: 9
Views: 4865

Re: Real or Fake Reticon SAD1024 Chips?

Problem is not with the chips. There is too much power going in through the filtering. 32 volts prior to the regulator, builds up to 22 volts after when plugged in. Will rebuild the entire section and cross fingers...
by pmkipp
08 Sep 2017, 00:22
Forum: Modern Stompbox Effects (1975 - ...)
Topic: Tech 21 GT2 Pops when turned OFF!
Replies: 1
Views: 854

Tech 21 GT2 Pops when turned OFF!

Any ideas how to filter this out? Works perfectly otherwise. Pop can get pretty loud. 1meg resistors from somewhere to ground? The schematic is widely available so I have attached one. Thanks.
san_amp_gt2_schematics.jpg
by pmkipp
25 Aug 2017, 16:09
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Real or Fake Reticon SAD1024 Chips?
Replies: 9
Views: 4865

Real or Fake Reticon SAD1024 Chips?

They look kinda fake, being purple and all. But the lettering is correct. These are in a non-working 1977 Memory Man (3 knob, solid gray version). Just some mild squealy noise when the effect is engaged. These have, besides the purple color and the metal label, gold pins and are mounted in sockets. ...
by pmkipp
25 Aug 2017, 15:42
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro PSFS-2 Footswitch Design?
Replies: 3
Views: 2940

Re: Maestro PSFS-2 Footswitch Design?

I have been researching/working on this and may have something to try when I get some free time. I will post any results
by pmkipp
18 Jun 2017, 19:44
Forum: Vintage Stompbox Corner ( ... - 1975)
Topic: Maestro PSFS-2 Footswitch Design?
Replies: 3
Views: 2940

Maestro PSFS-2 Footswitch Design?

Anyone ever tried to build one of these to work with the Maestro PS-1A Phaser? Would love to figure this out.
by pmkipp
18 Jun 2017, 19:40
Forum: Pedal Debugging & Troubleshooting Support
Topic: EHX 4 Knob Deluxe Octave Multiplexer Schematic?
Replies: 5
Views: 408

Re: EHX 4 Knob Deluxe Octave Multiplexer Schematic?

Never mind. There was enough clues on the 5 knob schematic to help me repair the pedal.
by pmkipp
14 Jun 2017, 17:40
Forum: Pedal Debugging & Troubleshooting Support
Topic: EHX 4 Knob Deluxe Octave Multiplexer Schematic?
Replies: 5
Views: 408

EHX 4 Knob Deluxe Octave Multiplexer Schematic?

Any schematics out there for the 4 knob EHX Deluxe Octave Multiplexer? Looking for the 1325C version, not the 5950 version which is readily available. They seem quite different.
by pmkipp
29 May 2017, 13:41
Forum: Boutique Stompboxes dissected...
Topic: Way Huge Green Rhino, MKI Schematic?
Replies: 3
Views: 1534

Re: Way Huge Green Rhino, MKI Schematic?

Thanks. It is an exact copy of a standard TS-9 Tubescreamer circuit, with different OpAmp and transistors. Otherwise, all the values are the same except for the Tone pot, which is 25k instead of 20k. The MKII is completely different.
by pmkipp
22 May 2017, 20:14
Forum: Boutique Stompboxes dissected...
Topic: Way Huge Green Rhino, MKI Schematic?
Replies: 3
Views: 1534

Way Huge Green Rhino, MKI Schematic?

Anyone? Have one in the shop, and when the tone control is turned all the way clockwise (to treble) the signal diminishes and gets a little freaky. Has to warm up for this effect to happen.
by pmkipp
22 Dec 2016, 17:45
Forum: Pedal Debugging & Troubleshooting Support
Topic: HELP! Snarling Dogs Mold Spore: V2 DPDT switch wiring
Replies: 0
Views: 44

HELP! Snarling Dogs Mold Spore: V2 DPDT switch wiring

mold 1.jpeg Someone bought me one of these. They had tried to wire in a new switch (don't know why), but had done it wrong. I looked everywhere for a picture of the guts of a Version 2 Mold Spore, but can find nothing. Even had some local musicians bring in their Mold Spores, but these were all Ver...