Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Instruments and Amps Everything that makes music, Especially including instrument amps.

arp pro/dgx power supply cap replacement
arp pro/dgx power supply cap replacement
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 8th June 2011, 01:47 PM   #1
us3rx is offline us3rx  United States
diyAudio Member
Join Date: Jun 2011
Default arp pro/dgx power supply cap replacement

I'm in the process of teaching myself and my daughters about electronics and music synthesis. Our fist project is a bipolar power supply (+-10 - +-15). I have a Arp pro/dgx that we are wanting to use for a chassis,keyboard,etc.. When I powered it up I got sound (a very loud hum that can be modifieid through some of the filter controls) and lights. I couldn't discern any pitch changes when hitting the keyboard.
At this point I thought we had are power supply ready made. Referencing the schematic I tested the output and found I was only getting +6.25-+6.4v d.c.on the +15v output. When I switch the meter to autorange AC/DC it will flash between +6.4v dc then to ~7.5ish ac. I'm going to replace the big caps first. I would like to use something off the shelf to replace just to test the circuit further. Can I use a Nichicon 330 my local Radio Shack in place of the 250? I've taken other measurements from the circuit both AC and DC which I can post if it would help.
Attached Images
File Type: jpg arppsver2schem.JPG (98.1 KB, 11 views)

Last edited by us3rx; 8th June 2011 at 02:09 PM. Reason: input more data
  Reply With Quote
Old 8th June 2011, 04:08 PM   #2
Nigel Goodwin is offline Nigel Goodwin  England
diyAudio Member
Join Date: Jul 2005
Location: North Derbyshire
Assuming they are actually 250uF, then 330uF would be fine - but 250uF is a very low value, so presumably it's only a low current supply? (notice the 3300uF on the other supply).
Nigel Goodwin
  Reply With Quote
Old 8th June 2011, 04:22 PM   #3
us3rx is offline us3rx  United States
diyAudio Member
Join Date: Jun 2011
thanks for the reply Nigel.
I checked the writing on the caps "250MF 50V" the part number is "TT50X250A". it measures roughly 1cm dia. x ~3.5cm length.
  Reply With Quote
Old 9th June 2011, 03:29 PM   #4
indianajo is offline indianajo  United States
diyAudio Member
indianajo's Avatar
Join Date: Jan 2010
Location: Jeffersonville, Indiana USA
Power supply caps can be up to 40% higher in value (before the turn on surge burns up something) or 50% higher in voltage rating (less the chemical effects cause something non-linear). Tuning circuit caps, usually rated +-10%, have to be matched by tight tolerance caps.
Nichicon makes 1000 hour caps and 8000 hour caps. I prefer the latter when working on something I might keep. I don't buy surplus electrolytic caps, they might be old, and the seal deteriorates on the shelf unused. Newark.com has the hours life in the selector tables to allow you to select the quality line. Other vendors you have to click on the link to the datasheet and read it. Panasonic, for example sells some caps with the same prefix, some of which are 1000 hours, some of which are 3000 hours. The more hours, the better the seal at the seams of the aluminum can. To keep my shipping costs down, on devices over 20 years since re-cap, I order them all on one order. I'm getting $6.70 UPS NC to IN. Mouser.com TX to IN is $9 minimum. From california I ask for USPS priority ship, it saves over the long distance.
You must live on the coast, because my local Radio Shack has telephones, toys, and batteries. No components.
Dynakit ST70, ST120, PAS2,Hammond H182(2 ea),H112,A100,10-82TC,Peavey CS800S,1.3K, SP2-XT's, T-300 HF Proj's, Steinway console, Herald RA88a mixer, Wurlitzer 4500, 4300

Last edited by indianajo; 9th June 2011 at 03:34 PM.
  Reply With Quote


arp pro/dgx power supply cap replacementHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
power supply cap replacement: NAD C370 nick78 Solid State 7 16th July 2009 07:15 AM
gold cap power supply ? Bernhard Digital Source 1 17th January 2008 07:21 AM
Power Supply Cap Values Noak Power Supplies 7 12th July 2005 08:34 PM
Cd Pro power supply CHS Digital Source 2 16th February 2004 08:40 AM

New To Site? Need Help?

All times are GMT. The time now is 09:29 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio