Lexicon PCM 70 Repair - Part 1

Repair of a classic Lexicon PCM 70. This particular unit is in very bad shape. It does not power up due to some bad integrated circuits and it has a bad display. I go over the PCM 70 architecture as I troubleshoot it and explain the process of isolating the faults. Once it is powering on, it has a 'Slave Dead Error' which will be discussed in part 2.

[@MalukahWithoutReverb]

This was awesome. Thanks for taking the time to explain. Looking forward to Part 2!

[@carriersignal]

Great video man. I have an Eventide H3000SE that I will begin working on here shortly. It has problems with the front interface buttons that I suspect are logic related. I too have a boatload of TTL / CMOS chips lying around enjoy keeping old studio equipment going. Looking forward to part two of your video. Hopefully you're on the home stretch.

[@onteraction8294]

Did you ever figure out your h3000se? I have the same issue it sounds like.

[@p8051a]

Excellent troubleshooting!Waiting for part 2..

[@cfcreative1]

I love the sound of this PCM 70 of all the Lexicons. I have an LXP 15. They are getting rare to find.

[@brandonwattz2924]

Hi Brad! I have a Lexicon PCM80 and it works but I have static/distortion when adjusting the gain/level knob and also, distortion when running sound through it! Can you repair and where are you located ?

[@antigen4]

holy crap - those boards off the intergraph stations!!! WOW. were those from one of their CAD/CAM computers? microstation i guess they were called?

[@wackenthaljef]

Wooow...Brad...My PCM41 is broken (its a delay ).....someone let a mic open and when i came back in the c room the leds of the in signal was all lighted ,i think a loop was created and cant stop ,i think there was no limiter on this model...so nothing more working.i cant find noone to repair it in France...shame!....Thks for this vid!

[@wilbstrange2]

When you finally get to the second part of your trouble shooting video, can you also video recapping the electro lyrics for the power supply of this unit? I own one and would love to learn more how to work on these things. I have one that’s 30 years old still sounds great however I was Curious how much better it would sound of the recap after 30 years? Do you do that kind of work? What would you charge to repair mind if I needed to have it done? Love your video keep it coming

[@MidnightVisions]

Is there a part 2 yet?

[@jimmoss9584]

Hey Buckwheat! Where is the battery?

[@riccardococcia]

My Pcm70 only outputs a dry signal now ( no wet signal ) after being transported for relocation and stored for over 1 year. Any tips on the first steps i can take to diagnose the problem?

[@РусланКраев-ы1л]

I have bought on eBay comlete set "Lexicon PCM70 Version 3.01 Eprom Firmware Upgrade Effect Reverb For PCM-70"... This is NOT work. The bought processors 3.1 Lex did not turn on ... When I touched these new processors - they were very hot. Returned to place 2.1. It works without problems. Nothing is warming up! What could be the problem??

[@Yupppi]

Figuring out this unit seems much harder than the spx90, scarier to think of grabbing one that doesn't function and fixing it, scoring an expensive unit for cheap. For this you definitely need more education/experience, tools and knowledge how to use them like oscilloscope with the chips.

[@NicoDAlessio]

hi there, i'm looking for a pcm70 display - anyone can help me? tnx

[@rodgedefender]

Hello, where can I find a new display to buy?

[@matthewaverill]

I second this question!

[@prasanthselvadurai3450]

Thirded

[@ingoodmusic]

Can I change battery myself without soldering?

[@theweakandthefew]

Hey Mr. Brad! Thanks for putting out this video. Are there jumpers that can change the output level? I sent one of mine for service and it came back and the output level is considerably less now... Hmmmm... Thanks! : )~

[@TheVisionites]

You can adjust the output level up to +4 via the front pannel user settings page on the pcm 80 so perhaps the same on 70?

[@theweakandthefew]

@@TheVisionites Thanks!

[@antigen4]

check your HV cap for the display I'd guess

[@antigen4]

any idea where to get replacement buttons? i'm missing one on my M300

[@Sickindian5]

Have you managed this unit to work?

[@silverlight2004db]

i've got a pcm80 and the analog input/output has stopped working. i have switched to using the s/pdif in/out which is working normally. i haven't opened it up at all and i'm not electronically minded. i was wondering if you have any ideas/advice based on your experience on what/where could be the problem...i live in bali and am not keen to send it overseas to a lexicon repair specialist while i can still use the digital in/out. dave.

[@TheVisionites]

Same issue here dave, seems your adc chip has given up the ghost most probably. there is a replacment chip availible on ebay, i have not attempted it yet

[@silverlight2004db]

@@TheVisionites thanks for reply...you prompted me to take my unit to a local tech guy and he wants to replace ADC...i have just ordered one from here : www.ebay.com/itm/333581608150

[@moursalinday2938]

bonjour j ai un probleme avec ma carte son lexicon non reconu en usb affchan un code erreur