Rowe Saturn Jukebox Amplifier problems

[lilshawn]

new insulators too. those metal cans CAN'T touch the metal AT ALL.

youll have to check the driver board too. they are the 4x4 inch boards on the back. sometimes some resistors burn out on there and some traces burn up. check them out and see if they look okay.

[ed12]

u c the rules for rebuild are comming in now
just keep in your mind we are here to help and not run u into the ground

ed

[amandandme197]

Sounds good Ed. Again, I can't thank you enough for taking your time and patience with me and my newbie  jukebox experience. I can play them, but fixing them is new to me. My fiance bought me it since I always wanted one, but was ever too sick to enjoy it. Now I am able to enjoy it, but just too poor to fix it.....But I guess it is a good thing I am still alive to fi it.

[amandandme197]

I thank you for that too

[ed12]

welp i am gonna save u a boat load of $$$ here
the new silcon i am refering to comes in about 4-5 sizes that i know of
get the 1 once size olny..that will be more then enough to do the job
the insulators are about 10 cents each..u need 4
plus if they came with what looks like white rings..they are actulay insulators also
alot of the time i salvage them from scrappers,but i do replace them also
resisters are about a dime each,caps rang but are cheap enough
i truly wish shawn or ken would hijack me and up-load a service manual..all i have is the rowe 100a cd manuals

ed

[amandandme197]

Well, I have  new insulators i pirchased with these last transistors that i never used due to salvaging the old ones. I have 3/4 tube of silcon grease left of a 1oz tube. I do not have the white rings, or transistors, etc.

[ed12]

as a rule when i go to a suppiler for the transistors all expect the grease comes in the pkg.
i know for a fact that if i buy ecg or nte >matched-pairs< the package states it
and comes with the full go..grease/mica's/insolaters :if used:?
some times the socket is made with the hole-throughs :chassic: instead of the white washer type insulater i am talking about..
so as long as u have grease and micas,u are good to go..

now do not just place these in when u get them..i want u to run some test's with me,what we do is bring the amp on with new fuses..and do some chks on the driver board's..i take it u do not have a scope.?...so i will need to go abit ol school
on these tests..do u have a spare audio reciever laying around ?..if so grab a pair of 1-4.7/mf-50 volt caps,we will want them to couple the amp stage's
this because we do not dc into the test reciever..at any time
we will problay go to phono input first >test reciever< then once we get to the finals we will go to line in..hence the reason 1mf and 4.7 mf
what we are duing in lue of a scope is coupling the sound out the amp..and doing some dc measurements on the way to see if there is other things wrong..as i supspect there is..so we want to nip it off in the butt
as shawn said >resisters< >burnt-traces< >cold solder joint's<
and i am looking for leaking caps..dc stuff right there
so even though this sounds like a pile of work..once u are done
u can high 5 and have at it

ed

[amandandme197]

Doing all that work is no problem, i am just happy you are helping me through it. I do not have a scope or a audio receiver though. What would be my next option? I think i may buy those transistors off the site  ken provided that come with two transistors, grease, and insulators. I will purchase that X2. I will not do anything with them once i get them and wait to  hear from you. What to do now without a scope or a receiver?

[ed12]

ok and good...we will save them new trannys till the end of this
no scope i kinda of took it as that..but no spare audio amp of any kind ?..most ppl
have something old laying around..rember i said we will go  ol school here
u do have a multi meter..that works in our favour..now rember i am not treding on u here..but do u know the scales and how to use them..? as that will be a lanuch point..rember without a scope and a spare reciever..i will need to dig deeper into my toy box.as it is said..but u have to answer me..another i need to know very badly..is do u own a soldering gun or a soldering iron ? as this will give me a better understanding,rember i am just setting the stage right now.so u do not wats your money,and get all pissie..i went through cardiac sugery 3yrs ago..so i know where u are comming from.glad u are better.. lets get this puppy fixed

ed

[amandandme197]

I do have a voltmeter/multimeter, but do not know what to set it on as it has numerous settings. I do have a soldering gun, and I have fixed many electronics in the past, but not to this extent. The voltmeter/multimeter has tons of settings, so I dont know where to start on using that. I know your not trying to beat me up, and just trying to figure out where I stand, what I have, and what I know. You are teaching me, and just asking questions you would need to know before we statt. Thank you very much ed. I have a bunch of transplant friends that are having failing organs, and going through cardiac surgeries, and they are no joke. Anything pertaining to the number one vital organ that keeps us alive and is under a rib cage is nothing that is fun. I am glad you are well too. It is funny how a lot of people have no patience for newbies, but this is how newbies learn. Everyone starts at the bottom, and works their way up. I am glad you have the patience. I really appreciate it. Are you in a US time zone, or are you in another country? Just tring to figure out the best time to work on this when we get going. Thanks again ed!

[lilshawn]

I don't have a digital version of the schematics. there was a site you could download them from, but they went to a pay site. should have scooped them while I could.

you don't need rings or anything on the screws. it's okay if they touch the metal can. they screw into the phenolic holder base that the transistor clips into so they remain insulated. you just have to make sure you don't have the shaft of the screw touching the side of the hole in the heat sink.

the phenolic base has some ridges around the screw holes that are supposed to keep the base aligned with the screw in the middle of the hole so there is no chance of it touching, but it's easy to think they are seated properly when in fact it's not since it's view is obscured.

this holder also makes it so you don';t have to solder the transistors at all, you just unscrew them and pry them out. be aware though the base isn't attached to anything and you may have to disassemble the boards from the backside to reach in there and hold the base while you attach the new transistor.

protip: when you are finished installing the transistor test for a short with a meter between the can and the heatsink. if it's in the 100's or 1000's of ohms it's okay, if it's zero, something is touching somewhere and the can is grounded. You will need to fix it before you power it up or kablamo!

[Ken Layton]

We never had any "I" series jukeboxes on our route so I've never seen one. The highest Rowe CD juke model we bought was the "D" series. We had tons of "A" and "B" models though.

I understand that around the "F" model, Rowe changed the driver boards in the amplifier to "self-adjusting bias". There were no adjustment trimpots on those driver boards because they adjusted themselves.

In my experience over the years, any time the output transistors blew out again after being replaced, it was usually because there were additional bad components on one or both the driver boards. I have no experience with the new self adjusting driver boards, only the older driver boards with the trimpots on them.

Definitely all four of the output transistors must be electrically insulated from the chassis/heat sink so be sure all the insulating mica sheets are there and smeared with a film of silicone heat sink grease.

[ed12]

amandandme197
its ok thats what we are hear for
all i will need from  u at the moment is the model # of your meter
so i can snag its pdf,then i can easily guide u the rest of the way
i cut my teeth on anlog meters..so its an easy walk for me
ken and shawn thk-u for chimming in
i will ask ron over at phonoland for a copy
or maybe ami-man has 1 he could scan for me >amp-olny<
ken i truly hope this is a self biasing amp:)
would save us alot of time..
i am in canada eastern time  zone
but usally i am on off all day

ed

[lilshawn]

All the cd100 series machines used the same amplifier. I have dozens of manuals here... We don't leave them in the machines.

I had an issue with the new style self adjusting boards and new transistors. damn things sounded like they were blown when in fact they where good. i ended up switching out the boards with the sapre (i put the new boards in the old transistors amp and the old boards in the new transistor amp)  and had no problems with either one.  i don't know what or if they changed in the transistors in this particular run i got or how the new boards self adjust, but i'll be damned if i know what the deal was.

ANYWAYS...

for the old style driver boards, you have to check R21 R24 R33 and Q4. especially if the board looks like it got hot. R21 and R24 should be 180 ohms R33 should be 470 ohms. if r24 is toasty q4 is almost assuredly shorted.

i'll take the manual home with me today and scan the amp section into a PDF and post it here tonight when i have a few minutes.

[amandandme197]

Hey ed, it is a Sears ohm/voltmeter model# 982364

[ed12]

ya basic meter
but good enough for us
shawn said he might beable scan in a pdf for the amp
and away we go
i have my cd100 manuals i will look tonight
just got done a monitor overhaul..so me eyes are a tad slow
bear with me

ed

[amandandme197]

No problem ed, thank you. These are the transistors I bought and will probably buy again if they are the right ones due to the price, but do these look right to you? Thanks

http://www.alliedelec.com/search/productdetail.aspx?SKU=70013781] [url]http://www.alliedelec.com/search/productdetail.aspx?SKU=70013781[/url]
http://www.alliedelec.com/search/productdetail.aspx?SKU=70013779]  [url]http://www.alliedelec.com/search/productdetail.aspx?SKU=70013779[/url]

[ed12]

your links are broke ?
but no never mind..ken thk-u very much
it is truly a self baising unit
thk-u shawn for stating the diode chain i see it now
when shawn up-loads a scan ? i can explain why they have to be matched pairs and give u cleariatiy
u will be looking at the driver boards
as something is not right
it is a starnted push pull amp 1-npn 1-pnp per channel
4 self biasing per side >heat sink mounted>
the transistors are high gain darlingtons >best to have some sort of a load on them at all times,we normaly use a 100-125 watt light for this
u have 2 leds that will tell u if the amp is overload condition
u have 2 fuses pre driver board to deal with
u have 4 high power resisters per driver board
to deal with..again thk-u shawn for the heat issuie
we will need to adress these
now my manual is covering 61024901/q2-q2 d
mine has some voltages..but lists all parts values
so if shawn dose not chim in witha scan ?
i am on the road tommrow i will stop and get a good scan done

hope this helps

ed

[amandandme197]

Sounds good ed, thank you. 2 fuses on one board are blown.  The first four transistors I replaced (only one channel was bad but I replaced all the transistors anyway) were Motorola, so I assume they were replaced one time before. I dont know if that helps at all

[amandandme197]

You know, it also would not surprise me if the screws touch the heat sink. There is some play when putting them in. I may be wrong

[lilshawn]

here you go...if you want any other parts of the manual, let me know.

https://www.dropbox.com/s/lfz304hk6sxi0gp/saturn%20amp.pdf

[ed12]

before u buy anything le me chk into my grab bag of fools here
i may have a better source for them matched pairs
until then,u can remove the driver boards and inspect for problems
u must rember the heat issuie shawn spoke off
with them 5 watt resistors  your gonna get heat , trace lifting,cold solder joints
etc etc..what as a rule we normal do for good measure is :re-cap:..there old and will not be with in range anyways..
and for the cost it is like a investement
your meter is easy to use
it will fill your needs on this 1
expect for the low range resister  >5watt< jobs i see in parrall as they are .3 ohm and in parall that comes to .015ohm..your meter may not be up to the snuff there
but again they are cheap enough >side on the favor of no error here<,
with the driver boards cleared up,we can move on to testing >with out the finals in<
for our proper voltages..if they are there and good..we can lock in the finals and give er a go..light load olny >150watt bulb<..i say that because i do not like snapping my drivers with a hudge dc thump..
so i always use a light bulb
now onto your meter
u will have what we call a range switch to switch between different ranges
so
dc-volts 2,20,200/ac volts 2,20,200 much like that
then u will have what is called a ohm scale 1k/10k/100k/1meg much like that
when we do dc voltages it is always refered to ground >chassic< unless i tell u different,if so i will spec where to place the probes
red will always be your + lead/ black will always be your ground lead
again unless i explain to u different
for resisters i will tell u what scale to go to,and u will place the probes >across< the resister in question..caps u cannot test right with that meter hence why u are doing a little shopping list to recap the unit..there is just no way with what u have that we can get the readings we are looking for..
for diodes u will go to your lowest ohm scale 2ohms for the sake of it
if u read 2ohms your meter will go all the way from left to right
that makes it a 2 ohm resistor
for a diode if u measure it 1 way and the meter dose not move u will reverse the probes and test it again,what u just looked for was a shorted diode or leaky..leaky can be a tad tricky on an anlog meter but we can get thourgh it
now a hint hear
if u go to ohms range :any: scale and short the probes the meter will deflect from left to right..dead short..

thk-u shawn
ed

[ed12]

in light of the doubt
remove heat sink
remove sockets..they will come out
inspect for broken insulater on the hole throughs
if u fig they may have done it error on the side of cutting wood
double measure twice cut once

ed

[ed12]

i just went through the pdf
shawns shows a biasing control on the diode board where mine dose not
we had better nail this amp rev down..
please chk that board for a control >biaising board on the heat sink<
there will be 2 if there there

ed

[amandandme197]

Oh boy.........

[amandandme197]

How do you connect a bulb, or know what looks bad,........my head is spining

[lilshawn]

How do you connect a bulb, or know what looks bad,........my head is spining

yeah ed's kind short and to the pint.

he basically says take a look at your driver boards and let him know which ones you have (the schematics i posted are 2 different kinds and part numbers.) let him know which you have. like we mentioned before, there where 2 different kinds of driver boards, an older one where you had to manually set the transistor bias by adjusting a trim pot, and a newer revision that did this adjustment automatically. (no adjustment necessary)

also to inspect the board for signs of burning hot parts. check the traces for lifting broken solder etc. darkening of the board.

test the resistors. you can look up the part designations and see what they are supposed to be and compare them to what you read. all values should be within about 5% (for example a 420 ohm resistor should be between 399 and 441 ohms)

resistors start reading higher and higher if they are beginning to fail or have been hot. and may read 100's or 1000's of ohms higher than it's supposed to.

[amandandme197]

Got ya shawn, thanks. I do know that the two smaller boards have two fuses each with one above the other, and each board has 3 red led's on it with two being close to each other, and the other more in the middle of the board.....if that helps. Also, how do i take these things out without cracking the boards, as the two smaller boards are plugged into the huge board.

[ami-man]

Hello amandandme197,

To take out the boards out of the chassis, remove the jumper plug on pre-amplifier and press on each of the pawls of the plasic clips that hold the pre-amplifier in place one at a time in order to lift the board at each point.
Remove the plug that goes to the mute connection on the board.

With regards to cold joints look at the pins on the jumper plug for any cracks on the solder around them, if there is a sign of cracking you will have to resolder the connection, do the same on the two connectors that go onto the pins from the driver boards.

As stated before now remove the driver boards the with the same method as above and check all of the pins again for cold joints and resolder if required.

Whilst you have the diver boards out of the chassis, look at the larger 2 & 5 watt resistors on the boards for any over heating or cracking of the surface coating, if that is the case then they will need to be replaced, some of these resistors can be very low impedance that has to be the correct value, also check that the solder joints on these resitors is good.

As already said make sure that the transistors that you have replaced previously are in the correct location and are insulated with the mica/plastic insulator that has the heat compound on it and that the fixing screws are tight in order to make the collector connection on each transistor.

For testing purposes I would fit a slightly smaller fuse to help protect the new transistors, a 5 amp should be ok without a load on the amp.

If the transistors or the resistors get hot staight away or if the 5 amp fuses blow then you have major problems that I fear are beyond your scope.

Regards
Alan

Alan Hood
ami-man
UK 

[amandandme197]

Ami Man, Thank you. I am still looking but don't see much. This is what I have. If anyone sees anything, please let me know. All solder joints look good.



http://www3.picturepush.com/photo/a/13798956/img/13798956.jpg[/img]

[ed12]

correct me here
but that looks like a self biasing  unit to me
refer to the pc in the middle of the heat sink

the resistors we are talking about are the 1's that look like big bricks
they look good
the boards look fine..no damage i can see

what we do now is some tests with that meter of yours..

also u may have either shorted out the outpus placing in the new 1's
and or forgot to do a few steps.? refer back to replys here
or your speakers are shorted and or the out put tramsormer..?

this is what the light test is for in its cleartly..so we can see load without the outputs
in...

ed

[amandandme197]

Ok ed, I have no parts and no spare fuse (they have not came yet). Can it still be tested, and how do i hook up that light? Thanks

[lilshawn]

yes those are the auto bias boards. 40710105.

no adjusting for you! 

the manual bias adjust driver boards are 40710104

you may still run into the issue where they "sound" blown like i did with those boards.

we will cross that bridge if it comes to it.

[amandandme197]

Nice. Sounds good. 

[ed12]

ok light test..
as long as your fuses are ok.?,chk them for NOT OPEN STATE,as per my meter refernce below,lowest ohms,see which the meter moves when u short the probes.
this is exactley want u want when u measure on either side of the fuse..
in short 1 probe on 1 end of fuse,other probe on other end..
meter must deflect all the way..i tend to lift 1 end of the fuse out,so i know i am olny probing >looking< at the fuse olny..

now on to light test..get any 40/60/100 watt house hold light bulb
solder 1 wire to the outside ring
solder 1 wire to the bottom center of the bulb
boom u got a light load..
a 40 watt for what we are doing is fine..but as your bugdet is small
any size just spec it to me so i can deduce what i will expect
WE WIIL NOT HAVE YOUR FNALS IN AT THIS TIME >FINALS=OUTPUTS<
first we will make sure your fuses are good..not by looking at them but rather by using your meter
we move on from there

ed

[amandandme197]

Got ya, sounds good. 2 fuses are for sure bad as the wires inside are melted in to two peices. I will  have to order some fuses for sure.

[ed12]

now that is where a few light bulbs wired exactley as i stated come in handy dandy
as u can wire in the bulb >jump< the fuse,and test along.....
now u know why i want light bulbs....
by now u should understand it

ed

[amandandme197]

Ahhhhh, so as long as I am using the lightbulb to test the amp, i can use foil to jump the fusees that are bad, or use another lightbulb wired up as a fuse? I am assuming you mean jump the fuse with foil.....

[ed12]

never never ever with foil or a soild piece or wire
that is is a very very bad no no
the bulb will persent a 4-8 ohm load
this is ok for testing
much like a fuse but not the same
were a fuse will :snap: foil will not/nor a piece of wire..in the trade we call that a crowbar,the bulb will either light or be drak or be some what lite,or will strobe
we want that....
full light means no load >good but we can test more<
full dark means full load>bad we need to stop right now<
strobe means passing audio>what we are looking for<
it is the easy way to save a few dollars and alot of fuses

ed

[amandandme197]

Ok, got ya. So the bulb will nut be used on the speaker outputs, but instead the fuse holders, and if so, beings there are two fuses per board, do i need 2 bulbs per board. Im catching on, but I skjust dont want to screw it up.