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Waldorf Pulse problem
Old 9th September 2013
  #1
Waldorf Pulse problem

Hi all,

I recently bought a faulty Pulse that has almost no output despite all functions being displayed and receiving Midi. I sent two emails to Waldorf asking for help with no reponse whatsoever. This is how the issue manifest itself:

The unit was not used for a long time before the error was discovered by its owner. The initialization of patches works and you can just faintly hear different basic tones when used with external MIDI keyboard. The ARP and LFO work and again you can just hear faint unfiltered waveforms. The ADSR or filter don't seem to work.
I tried the unit with both 1.42 and 2.01 ROM software and the same issue persists.
I went through SER (service) program and following was noticed:

- TUN produces nothing and LED is blank

- HTN produces 14.9 on LED

- TST produces FLT and everything blinks including LED display and LEDs

- OFS, nSE, VCA, SAV and STc all produce E. 1 displayed.

Anyone has any ideas what could be causing this or can provide Puse schematics so I can trace the signal and see if it's generated and where is it broken?

Big thank you for anything useful!
Old 9th September 2013
  #2
My unit had some problems, replaced electrolytes, works good again ever since. I'd start there first. And then go inspecting.
Old 9th September 2013
  #3
Thank you, I'll try that.

Just to clarify, you meant to say same problem, not some, right?
Old 10th September 2013
  #4
Not a typo.

Many Pulse units were working 24/7 since there's no on off switch, and could have dry capacitors (if the batch was bad). So these are first suspect.
Old 14th September 2013
  #5
I am definitely going to exchange the capacitors at some stage but I can see that this is not causing the issue unless capacitors are bad in the internal power supply.
The signal from all three oscillators is just not being mixed and processed. I traced it to the point of resistors before the mixing stage.

Does anyone know for sure what voltage should be read against ground on supply terminals 4 and 11 of op amps TL064?


Thanks!
Old 24th September 2013
  #6
Me again, very stubborn bugger I am, decided to really pursue with this repair so I bought another faulty Pulse to compare them.
The second one has full output and oscillators are nicely mixing, arpeggiator is working but there is no envelope and filter is bypassed.
I can see that supply voltages on op amps TL064CN are the same so I don't blame the power supply on either units.

Now, does anyone know which op amp is in charge of the envelope, out of 5 TL064CN or is it the TL074CN, the only one there?

Thanks!
K
Old 10th November 2013
  #7
Just to report back on this one. I have managed to repair both synthesisers. I found schematics on yahoo group for Waldorf Pulse and this helped hugely. One unit had IC1023, TL064CN in charge of CV levels 3 and 4 burned and needed replacement. The other Pulse had IC1027, TL071 dead, in charge of getting voltage levels sent from DA converter to multiplexers. This proves that those JFET OP amps are sensitive components in a Pulse supported by the fact that one of them already had output replaced, instead of TL074 there was new TL084.
Hope this helps anyone looking to get their Pulse back to life.
Let me know if you need more details.
I'll be selling one of them soon so if anyone is interested in the UK please reply here.

K
Old 11th November 2013
  #8
Sorry, i have to correct myself. The schematic is at yahoo group vintagesynthrepair files, not Waldorf one.
Old 15th March 2014
  #9
Lives for gear
 

Quote:
Originally Posted by kloopy View Post
Just to report back on this one. I have managed to repair both synthesisers. I found schematics on yahoo group for Waldorf Pulse and this helped hugely. One unit had IC1023, TL064CN in charge of CV levels 3 and 4 burned and needed replacement. The other Pulse had IC1027, TL071 dead, in charge of getting voltage levels sent from DA converter to multiplexers. This proves that those JFET OP amps are sensitive components in a Pulse supported by the fact that one of them already had output replaced, instead of TL074 there was new TL084.
Hope this helps anyone looking to get their Pulse back to life.
Let me know if you need more details.
I'll be selling one of them soon so if anyone is interested in the UK please reply here.

K
I have a faulty pulse. Can you post schematics? Thanks!
Old 1st March 2016
  #10
nvs
Here for the gear
 

I found it here "schematics"
https://groups.yahoo.com/neo/groups/WaldorfPulse/files
Old 21st July 2018
  #11
Gear Maniac
 

Brought my Pulse 1 out of storage (4 years). All lights and display working inc receive midi light but no sound.

Anything someone with zero electronics background can try?

Anybody recommend a tech based in the North of England?
Old 3rd September 2018
  #12
Gear Maniac
 

Bump for tech
Old 18th August 2019
  #13
Gear Maniac
 

Quote:
Originally Posted by Diel View Post
Brought my Pulse 1 out of storage (4 years). All lights and display working inc receive midi light but no sound.

Anything someone with zero electronics background can try?

Anybody recommend a tech based in the North of England?
Just tried the Pulse again (never got around to finding a tech) and its back working! Big smiles here as was toying with picking up a replacement
Old 19th August 2019
  #14
Lives for gear
 
namnibor's Avatar
Quote:
Originally Posted by Diel View Post
Just tried the Pulse again (never got around to finding a tech) and its back working! Big smiles here as was toying with picking up a replacement
The little demon that lives inside does need to sleep from time to time.
Old 4 weeks ago
  #15
Gear Maniac
 

Quote:
Originally Posted by namnibor View Post
The little demon that lives inside does need to sleep from time to time.


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