Roland TR-808 power on issue - Gearspace.com
The No.1 Website for Pro Audio
Roland TR-808 power on issue
Old 21st September 2012
Here for the gear
๐ŸŽง 5 years
Roland TR-808 power on issue

Hi there!
My 808 problem is that after switching it on it doesn't work the first 2-3 minutes.
- "Basic Variation" and "1st part" LEDs are on, but the "first-step-LED" doesn't blink (as it should be)
- pressing Start/Stop button results in nothing
- crackling sounds on all outputs

after a while its "sleep mode" is gone and everything works.
after switching it off and shortly afterward on again the machine works.

additional info:
--built-in Groove Electronics Midikit
--battery was wrongly inserted for some time when the machine wasn't in use

any ideas what could be the reason? power supply?
Old 28th September 2012
Lives for gear
acreil's Avatar
๐ŸŽง 10 years
Check the power supply first. Often faulty components (electrolytic capacitors) can improve some when they've warmed up. There's also a CPU reset circuit that might be malfunctioning.
Old 28th September 2012
Lives for gear
๐ŸŽง 5 years
Crackling sounds could be a leaky transistor letting the white noise signal through. I had this with a 909 once. This could also be caused by a power problem if the correct trigger signals aren't getting to the analogue circuits.
Any revisions in the schematic for the CPU reset circuit? This was a problem with some 909's. If there is something wrong with the power supply it might not be stabilising quickly enough to power the CPU properly and you can get chain reaction problems through the circuit.

Check if the CPU is working properly first.

Are you sure all the buttons are working properly? If there is a button that you never use it could be short circuited and this will stop things working properly or it may have a very small resistance across it. If the power supply is OK I would guess that there is a sticky button or switch somewhere that is stopping it booting up. I don't have an 808 so I'm guessing, but if the step buttons are like the ones on a Teisco SX-400 they are gold plated and they should be OK, but if they are not or there is a step button that never gets used or has a dual function check it works properly.

The main start/stop button type are prone to tarnishing inside. Roland had 2 types that I know of, one with a metal shaft and so they fill up with rust inside the switch mechanism, and one with a plastic shaft. The plastic ones sometimes can be got to work again with some decent switch cleaner but they can tarnish as well. I have changed a few in CSQ-600's before now.

Maybe there is a problem with the memory protect part of the switch. Any memory issues will stop things working properly. Switching things on and off quickly can sometimes make something jump into action. Maybe a memory chip enable signal isn't getting through at the right time.

Apologies for poor punctuation/sentence/paragraph structure/repetitions.

In summary, check the buttons all work properly and any with a dual function particularly.
Old 30th September 2012
Here for the gear
๐ŸŽง 5 years
thanks for your replies.
I have to add that the machine was in repair because of malfunctioning noise generator some months ago (crackling sd, claps and toms). The guy at the repair shop also made an overall test and exchanged some step buttons; the startStop button also was more smooth-running then.
So the overall performance is very good, but I always have to wait some minutes before Mister Roland is ready.
So apparently it's the Power supply?
Old 5th October 2019
Here for the gear
Buddspencer's Avatar
Same issue

Hello Patrick. The issue you described 7 years ago is the same one I have today with my 808. It sometimes need 5 mins to get the sequencer going and sometime longer.

Did you end up finding out what the issue was?

Old 18th September 2020
Here for the gear
๐ŸŽง 5 years
Hey all,

Stumbled upon this time capsule in my own quest to fix the slow-start issue with my customer's 808. For posterity, I'll leave my findings here.

I am 90% certain replacing the reset/muting FETs did it for me. They are 2SK30A's, two in GR Idss class and one in Y class, however I used -Y's exclusively with no issues. The differences are small. These are Q64, Q75, and Q13 in the service manual. Two are located above the fine speed pot and one is to the side of the master volume.

I've seen enough of those FETs go bad to always suspect them in repairs. Hope this helps!
๐Ÿ“ Reply
Post Reply

Welcome to the Gearspace Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.

Slide to join now Processing…

Forum Jump
Forum Jump