Skip to main content

Seeburg SHP3 Tone Issues


I noticed in my Seeburg Entertainer  (STD2) that the tone seemed to change randomly and that even with minimal treble there still seemed to be too much high frequencies.  The problem was especially bad on worn records.

What I did:

I decided to take off the pre-amplifier board and inspect the tone switches. Below is what I found.


As you can see the switches were extremely dirty.
I cleaned the switches up with a rubber eraser and some deoxit.  (I forgot to take after photos)

Capacitor Mod:

Also, while I was working on the board I changed out the 2 1.5uF capacitors on the treble switch for .33uF capacitors. All I had in stock was 630volt. They are  over kill for the circuit, but they work.

After the cleaning and modification the amplifier sounds much better and did not have any issues with the tone changing while playing. 


Labels:

Comments

  1. Greg GOctober 24, 2018 at 6:58 PM

    Having similar issue with an SHP1 amp. It’s a bit too bright on highest treble setting, but muddy on the MED and MIN settings. The brightness is passable on mint 45s but even slightly worn 45s play with some light distortion. (Especially noticeable on the vocals) Would your fix here work for the SHP1, you think? Thanks in advance - Greg G

    ReplyDelete
    Replies
    1. CodyOctober 25, 2018 at 5:28 AM

      Greg,

      It should work just fine. I will follow up and say that the room your Jukebox is in will also make a difference in tone. My Seeburg Entertainer is in a large garage with concrete floors and hard walls. If your Jukebox is in a room with more objects to absorb the sound the tone will be different.

      One last note just for reference. The larger the capacitor in mfd the more high frequency drops. You may need to experiment and find the correct one for your setup.

      Hope this help.
      Best Regards,
      Cody

      Delete

Post a Comment

Popular posts from this blog

Seeburg Digital Control Center

The Seeburg Digital Control Center came into use around the 1970's. This was model DDC1. Seeburg continued the use to the digital control center line until around 1977. The last model used was a DCC42-56. The DCC is used to supply 27 volts DC, -27 volts  DC and -13 volts DC to the jukebox. The DCC has test points on the side to measure these voltages.  Below you can see a DCC3. Once you flip over the DCC you will see two circuit boards. The top board is the data buffer board. Generally you will not have any issue with it. The second board (on bottom) is the power supply board. This where you may have issues. The power supply board is where the DC voltages are created and regulated. Below is the power supply board removed. The first thing I always do when working on a DCC is start by replacing all electrolytic capacitors. Below is the schematic.  In my case as you can see below I had other issues. As you can see transistor Q3120 has been repla
Post a Comment
Read more

Seeburg SHP3 Repair July 2017

I have just finished repairing this Seeburg SHP3 for a friend. My friend collects and refurbished jukeboxes and he occasionally brings me the amplifiers. Initial Photos : The above photos show the amplifier as I received it. It was obvious someone had done some work before. The driver transistors as well as the output transistors were not originals. Also, Q5114 had been changed. It is the big silver transistor you see on the driver board. The initial power up  using a dim bulb tester showed that the right channel was not working and too much current was being drawn. Why I use a dim bulb Tester:  Notice the red enamel wire running along the top edge of the driver board. A trace should be there, but someone ran the amplifier with shorted transistors and burnt the 32+ volt trace off the board. Repairs: Replaced Q115 and Q116 (Driver Transistors Right Channel) -Shorted Replaced Q5117 and Q5118 (Output Transistors Right Channel)- Shorted Replaced Q5114 (Signal
Post a Comment
Read more

Bell & Howell Oscilloscope Model 34 DeVry Tech

The Bell & Howell Oscilloscope Model 34 was purchased at an auction and then give to me. It was made by Heathkit for DeVry Tech (DeVry University). Below is a photo of the front after I finished electronically going through it. There was nothing interesting that came up while working on it. Below you can see some before and after of the underside. Below is the top side. The 2 filter cans were 4 sections of 20mfd for a total of eight 20mfd capacitors.  Below is the solution I came up with to replace them. It consists of eight 22 mfd on a PCB that is zipped tied to the bottom of the chassis.   Overall this is a simple oscilloscope and was a simple electronic restore.  Here is the schematic.
3 comments
Read more