Results 1 to 7 of 7

Thread: Sunn Sentura Tremolo Fix - Dead CDS cell

  1. #1
    Supporting Member Drewline's Avatar
    Join Date
    Feb 2012
    Location
    Colorado
    Posts
    216
    Thumbs Up/Down
    Received: 6/0
    Given: 12/0
    Rep Power
    8

    Sunn Sentura Tremolo Fix - Dead CDS cell

    I've been trying to resurect a Sunn Sentura I. The amp is a real science project. While it has a rectifier tube & socket the power transformer is missing the 2 yellow leads to supply 5 VDC to the rectifier. I fabricated a solid state rectifier tube which works fine plugged into the original socket. After cleaning up the wiring & the soldering everything worked except the solid state tremolo. The oscillator was working powering the original lamp. No volume change. The CDS cell in Sunn's version of the Fender bug was dead. As I have said in previous posts, I spent many years working as camera repairman. I got some surplus cells from junk cameras from a friend & found that they were the wrong sensitivity for this circuit. The internet lead me to Allied Electronics who actually sells CDS cells made by Silonex. I spent considerable time with the spec sheets finding a suitable replacement cell. It is: Silonex NSL-5160 The cell fits inside the original housing, the tremolo is now strong. I did replace the 6 electrolytics in the circuit after I confirmed the bad cell.
    The cell is the black object in the photo. I used Pliobond covered with black paint to glue the cell back into the housing & to secure it to the PCB as it originally was.
    Here is a photo of the Reverb / Tremolo PCB used in this amp.

    Click image for larger version. 

Name:	SSCN3790.JPG 
Views:	204 
Size:	71.2 KB 
ID:	36893

    I hope this helps!

    0 Not allowed! Not allowed!
    Drewline

    When was the last time you did something for the first time?

  2. #2
    Supporting Member loudthud's Avatar
    Join Date
    May 2006
    Location
    Near Dallas Texas
    Posts
    3,477
    Thumbs Up/Down
    Received: 149/0
    Given: 88/1
    Rep Power
    18
    Any idea what light bulb was used?

    0 Not allowed! Not allowed!
    WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
    REMEMBER: Everybody knows that smokin' ain't allowed in school !

  3. #3
    Supporting Member Drewline's Avatar
    Join Date
    Feb 2012
    Location
    Colorado
    Posts
    216
    Thumbs Up/Down
    Received: 6/0
    Given: 12/0
    Rep Power
    8
    It worked & was glued in real well so I left well enough alone. Looks like a grain of wheat type bulb probably 6V. The schematics call for 4.5Vdc across the bulb.

    0 Not allowed! Not allowed!
    Drewline

    When was the last time you did something for the first time?

  4. #4
    Member patlaw's Avatar
    Join Date
    Jun 2012
    Posts
    207
    Thumbs Up/Down
    Received: 50/0
    Given: 21/0
    Rep Power
    7
    There is some really useful information in this thread. I wish there were some better pictures. How did you get the old cell out?

    Marked for future reference. Thanks.

    0 Not allowed! Not allowed!

  5. #5
    Supporting Member Drewline's Avatar
    Join Date
    Feb 2012
    Location
    Colorado
    Posts
    216
    Thumbs Up/Down
    Received: 6/0
    Given: 12/0
    Rep Power
    8
    The cell was glued into the the housing. I gently seperated it after unsoldering both ends from the board. I used black nail polish to glue the new cell in.

    0 Not allowed! Not allowed!
    Drewline

    When was the last time you did something for the first time?

  6. #6
    Member patlaw's Avatar
    Join Date
    Jun 2012
    Posts
    207
    Thumbs Up/Down
    Received: 50/0
    Given: 21/0
    Rep Power
    7
    Did you save the old one, by any chance? I'm curious as to whether it was a "loose" cell or whether it was in a can, like the replacement you used.

    0 Not allowed! Not allowed!

  7. #7
    Supporting Member Drewline's Avatar
    Join Date
    Feb 2012
    Location
    Colorado
    Posts
    216
    Thumbs Up/Down
    Received: 6/0
    Given: 12/0
    Rep Power
    8
    The cell was in a housing same as the replacement. I return parts changed to the customer always. I see no reason to save dead parts.

    0 Not allowed! Not allowed!
    Drewline

    When was the last time you did something for the first time?

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Sunn Sentura II - Cap PolarityQuestion
    By earache in forum Maintenance, Troubleshooting & Repair
    Replies: 9
    Last Post: 08-26-2015, 05:02 PM
  2. Help with a 68 Sunn Sentura II
    By shiner555 in forum Maintenance, Troubleshooting & Repair
    Replies: 14
    Last Post: 03-19-2015, 02:10 AM
  3. Replies: 11
    Last Post: 03-03-2015, 03:54 PM
  4. Sunn Sentura II low frequency oscillation
    By booj in forum Maintenance, Troubleshooting & Repair
    Replies: 10
    Last Post: 07-15-2014, 06:58 AM
  5. Sunn Sentura 2
    By Mars Amp Repair in forum Maintenance, Troubleshooting & Repair
    Replies: 9
    Last Post: 06-05-2007, 09:46 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •