SHP3 AMP test points

I have Tony Miller's SHP amp book but I'm having trouble with readings at -32 to Q16 and Q26. books says less than 1 ohm i'm getting 105 ohm. Also from Q15B to Q16B and Q25B to Q26B i'm reading 1700 ohm instead of the 75 - 150 ohms. I just don't see what I'm missing.
Any help would be greatly welcomed. Thanks Don

What page of the book ?
Ron Rich

page 39

I had replaced Q5115/5116 AND Q5125/5126 but now it looks like 15 and 16 are bleeding by from the collector to the base. I'm going to change and see if this makes a dif.

You are aware of the errors on that page--I hope---Which code SHP do you have, and which PC boards are installed--and what is the problem you are attempting to fix ? Ron Rich

Yes I made notes of the changes from the posts. I have a code A boards 70-319295-A and 70-319270-A. Recapped unit and I have been going through test points from pg 39 5. a through n. g i'm getting 80 ohm and h i'm getting 460 ohm and not the 1 ohm or less. also the points Q15+base to Q16-base i'm getting70 ohm and on Q25+base to Q26-base i'm getting 2k ohm this amp is the shp1
This amp was from a unit that didn't work ( starburst ) I also have a mardi gra unit that has the same problem but it has the shp3 in it.

I did find a shorted stabistor 309478 but i'm having trouble finding anyone who carries the replacement listed on pg55 of Tony Millers book. Any suggestions?

This is very similiar to the problem i'm having, I can't find anything that refers to this in errors of printed material. Am I over looking something?




Subject: Re: [Jukebox-list] Seeburg SHP2 Amp Continuity Checks
From: Ron Rich (ronn...@yahoo.com)
Date: Jul 23, 2012 5:15:57 pm
List: com.netlojix.lists.jukebox-list

Iain,
Go to www.phonoland.com --then the "jukebox section"--then the "Errors known inprinted material". There are some errors in that book. Ron Rich

--- On Mon, 7/23/12, Iain Jamieson <pinb...@xtra.co.nz> wrote:

From: Iain Jamieson <pinb...@xtra.co.nz>
Subject: [Jukebox-list] Seeburg SHP2 Amp Continuity Checks
To: "juke...@lists.netlojix.com" <juke...@lists.netlojix.com>
Date: Monday, July 23, 2012, 4:42 PM

Hi,

Using the Seeburg SHP Amp book, I'm failing a test in the trouble shootingsection 6 parts A & B
I can not get a reading of 75 - 100 ohms across Q15 Base and Q16 Base. Likewisefor Q25 and Q26.
I get 6.9 Mega Ohms across Q15/16 and 6.25 Mega Ohms across Q25/26.
Am I correct that this step is reading the Bias Circuitry, I have measured the10ohm resistor, I have replaced the stabistor with a pair of 1n4148 signaldiodes wired in series. I get 83 ohms across the Thermister at room temp. It hasthe jumpers on the Driver board.
Any thoughts on what I have missed here?

I read up about the corrections in the book to section 5.
It's a SHP2 amp, but has a SHP3 Driver board installed #319295-B

Any thoughts appreciated.

Cheers

Iain

It looks to me that from pg 39 of the amp book, procedure 5,step g and h should read 100 ohm instead of the less than 1 ohm as stated. in both cases it looks like one should see R5176 and R5199 which are both 100 ohm. Yes?
Also if I take CR5116 and CR5117 they read 1170 on diode setting and 414k ohm setting. When in the circuit pg 39 Step 6 a), b), looking at 1200 Ohm.

I have never done those tests--just attach your "dim bulb tester" to the line, and two meters to the drivers as stated somewhere in that book, and see if you can set the bias. If so--you are OK. Ron Rich

Tried to adj. bias right channel adj fine left not at all. Not sure why yet. At least it go up in smoke!

If you used a "dim bulb tester", it will not "go up in smoke"--that's the whole idea behind it--
Check the pot first--Deoxit will clean it. What readings are you getting on the good and bad channels ? Ron Rich

Kept the dbt on all the time. right channel 1.6 and left 0 volts each being measured from Q16,15 and Q25,26 base
both pots were removed and ohmed each were maxed to 80 ohm down to 5 ohm
I'm also seeing voltage on Q5125 b,e and collector for some reason

Monte,
There are only a few things in that circuit--the power trannies, (be SURE mica is installed, proper heat sink compound installed, and no shorts to case exist--and of course, they are good, and the mounting screws are tight). The "driver" trannies ( use a TIP 31 C and TIP 32 C). The small "Q124" tranny. Under the heat sink--the dual diode, and the thermistor (which I have never seen fail), the .2 "sand-block" resistors--many failed units here--and of course, any other resistor on the board, or under the heat-sink, that's in that circuit.
While you are looking at that board, be SURE that C 5146 is NOT mounted in the center of the board ! If so, it MUST be moved to directly connect at the E-B of Q 16. HTH Ron Rich

Thanks I'll do more checking based on your suggestions. Your help is appreciated.
Don