Rowe Saturn Jukebox Amplifier problems

[amandandme197]

I have a rowe 61024903 amp for a Rowe Saturn Jukebo, and one side got all kinds of static and low volume along with blown fuses. I replaced the transistors with ST transistors, and replaced all the fuses. Hooked it back up, it made this weird astroids arcade game sound, blew 2 fuses on one side and both sides sound like garbage now. Anyone have ideas?

[Ken Layton]

I'm not familiar with the "Saturn" marketing name. What is the model number of the jukebox?

[ed12]

all rowe jukes used matched output pairs
if u replaced them with off the self replacements ? and did not re-bias the amp
guess what is gonna happen ??
also if it sounds like static..cap kit is in order
start from scartch..replace all transistor's,make sure the finals are a matched pair
re-cap,re-bias..carry on
a owners manual is handy right about now
as u need to :match: the rowe outputs to there :exact: spec

ed

[amandandme197]

Hey Ken, it is the 100i I believe. Ed, I am not electronicaly inclined and not certain of what you are saying (sorry) but I just replaced the transistors with the same transistor #s in the same numerical order they were. I put in new fuses, but do not know what the bias is, etc. I can't afford to get this repaired, and am trying to do it myself all from forum reading. I am lost. When I say static, i mean you can turn it up low, medium or full volume  and it sounds like the speakers are shot, but i checked them, and they are working fine. Also, the volume is very low at full volume. What it sounds like is what was explained in previous posts with transistor replacement, but that was all i did . I am capable of doing what needs to be done to get it fixed (i think) but I just don't know what to do, and or how to use a multimeter. If someone could help me out with the directions, I would greatly appreciate it. Thanks much guys.

[ed12]

i can walk u through biasing
but u will need a multi meter >digital i trust<
and the service manual..unless ken can chime in and tell me the bias voltage and resister to test across

ed

[amandandme197]

I have a non digital multimeter, but I have the manuals. Before I do this though, I need to get more transistors again, and fuses? Thanks

[ed12]

ok just ring me up when u are ready
make sure the outputs are matching..ie same beta/gain..etc
thats very important

ed

[lilshawn]

you basically need to have a pair of transistors that are matched very close. if one is different than the other it can cause a cascade effect that makes the transistors run away as they flip flop out of control till they blow up.

also, check the little circuit board on the underside of the heatsink with 2 diodes and 2 wires. they use it perform a temperature compensation. if there is a bad or broken solder joint on there it can cause the transistors to pop. about 90% of the boards i've checked have insufficient solder to hold the leads properly. the vibrations from the subs can cause it to break.

[amandandme197]

Will do ed. I will check lilshawn. I am using ST 2n6287 and ST 2n6284. I bought them from allied electronics online. What do i need to look for on the transistors besides the number? Thanks

[ed12]

thk-u lilshawn
i did forget that point in case

the transistors will have a suffix >mp<= matched pair
dose not matter if there both npn/npn  or pnp/pnp or a mix of the 2 pnp/npn
the suffiex must state >mp<

ed

[amandandme197]

Is there any wzy you could find them for sale on a site for me to purchase reasonably cheap? Thanks much

[ed12]

there is an op here that goes by the handle ami-guy
drop him a line :pm:
he may beable to help u.?
if not post the exact manual rowe #'s i will chk my manuals

ed

[amandandme197]

Will do, thanks so much.

[amandandme197]

Ok, in the parts manual I got this:
part no 70030206  Transistor (Darlington Amp, RCA-2N6284)(NPN, Q101, 2 places)
part no 70030207 Transistor (Darlington Amp, RCA- 2N6287)(PNP, Q102, 2 places)

[amandandme197]

Oh, i tried searching for ami-guy, armi-guy, army-guy, etc, and couldn't find anybody.

[ed12]

ami-man

my typo

>ami-guy<

ok so it is npn finals ? so both channels use npn ?
as outputs ?
please post me a picture of the final >output stage of the amp
so i can see it


ed

[Ken Layton]

Transistors can be purchased here:

http://www.cdadapter.com/repair.htm

Just scroll down to "Repair Parts".

Also here:

http://www.rowejukeboxrepair.com/

[amandandme197]

Thank you. Those look like the same number transistors i purchased first, just a different brand.

[ed12]

thank you very much ken.
go easy now the nick is  newbie to this..

ed

[amandandme197]

Ok, I am going to purchase those transistors, and hope they work. If they don't, I think I may put the amplifier in my backyard and use it for target practice.

[ami-man]

Hello amandandme197,

You do not leave your name or the country you live in, this is a world wide forum could you add the information to your profile.

If you are in the USA I would go with Kens advice and source the transistors from a reconised dealer such as he suggests or send the amplifier to Bruce Wentworth at A & B leisure to have it proffesionally refurbished.

If in Europe or the UK by mall means contact me for the same service.

Regards
Alan

Alan Hood
ami-man
UK

[amandandme197]

Im in the USA. I will go ahead and order the transistors. Thank you

[lilshawn]

2 x 2N6284
and
2x 2N6287

i would avoid e-bay... most of them are fakes. order from cdrepair.com, mouser, or digikey.

[ed12]

yes amandandme197
follow there advice..if u have never done this before.? it is wise to seek the help of ppl whom do it all day..
but that aside if u want to do it..ring me up i will guide best i can

ed

[ed12]

npn pnp so it is a push pull amp
u MUST chk the biasing  of these
and for the love of god make sure they are marked >mp<
or u will not get the bias right
aslo chk the diodes..

ed

[amandandme197]

Thanks ed. So the ones Ken listed are the right ones, right? They are MP? I will  have to do it myself Ed. Im broke. I have a 3 million transplant bill i am paying off, and meds that are over $5000 a month. This will have to be a do it yourselfer for me, and I will need help.  I really appreciate it

[ed12]

that's what we are here for is to help
sorry to hear about health issuies
but when u are ready i will get out my bag of toys
i am sure the other nicks will chime in also

ed

[amandandme197]

Thank you very much Ed. Health is better now due to the transplant and meds. Before i purchase,are those resistors ken listed mp?

[ed12]

i would have to think so
ken like me like a few other top knotch nicks here
do them all the time
and i have never found any problems with what he suggests

ed

[amandandme197]

  Nice, thank you buddy.

[amandandme197]

Hey ed, if you look at that second store Ken listed (Rowejukeboxrepair) or something like that, one transiztor is an mp and the other is not. The ones i installed, one is an mp, and one is not. I will take a pic

[ed12]

mp as i stated means matched pair..ie same spec's totaly 100%
so lets say beta on the pnp was 60% the npn must match it..
same with v-breakdown voltage ..lets say 100volts max on the npn..the pnp must match..same with gain..ihef lets just say 70% >gain factor< the pnp must match it..
hence the reason for matched pairs..or we just roll the dice and trough in any old pair,bais and hope for the best..

ed

[amandandme197]

Ok I see what your saying. There are 4 total, and as long as two on one channel match the two on the other channel the exact same.[/URL][/img][/URL][/URL][/img][/img]

[amandandme197]

[amandandme197]

[ed12]

after going through kens link

>"Rebuilt" 250 Watt Stereo Amplfier 61024903 /Exchange
You must first send in your exchange Amplifier 61024903 Once we receive it in, we will then send you out a "Rebuilt" replacement Amplifier the next day. The following >>"New Parts are included with each "Rebuilt" Amplifier that we do. 2 "New Driver boards. "New Pre-Amp board, 4 "New Output Transistors <<and much more. All "Rebuilt" replacement Amplifiers come with a 90-day <

follow the >> as what u need to do

also matched set means the npn and pnp of the same channel match

ed

[amandandme197]

all I can afford right now are the transistors. I cant afford all that other stuff right now or in the near future.

[ed12]

well my last post never made it up hmm
in your last pic..u can clearley see the word >mp< foward on 1 and reverse on the other..
as a rule they are sold as :pair's: for that exact reason..

now on the other parts..thats what we are here for to help u fix it cheaper then sending it in,so it may need a few diodes and caps,resiters..have at it
10% cheaper then sending it..and 100% better knowing u did it yourself
heres the trick..go slow and steady..listen up :alot: and carry on
rem u are the person doing the work. we are olny guiding u and are your personal sounding board until u have fixed..then its high 5's and we all go back to our corners

 ed

[amandandme197]

well my last post never made it up hmm
in your last pic..u can clearley see the word >mp< foward on 1 and reverse on the other..
as a rule they are sold as :pair's: for that exact reason..

now on the other parts..thats what we are here for to help u fix it cheaper then sending it in,so it may need a few diodes and caps,resiters..have at it
10% cheaper then sending it..and 100% better knowing u did it yourself
heres the trick..go slow and steady..listen up :alot: and carry on
rem u are the person doing the work. we are olny guiding u and are your personal sounding board until u have fixed..then its high 5's and we all go back to our corners

 ed

Awesome, thank you. I am going to start with Transistors to see if I can get it up and running, and then, slowly get the parts you posted. I will let you know when they come in. Is that ok, and do you think I still need to Bias the amp if I get those transistors from the guy Ken requested, or do you have to bias anytime you replace them?

[ed12]

as a rule u re-bias every time u replace an output
also do your self a fav do not put in the new 1's just yet
get them in by all means,but lets get a part list toghter here..
maybe ken can post us a link of the exact schmeatic ? so i can clearly see it
and stop talking out of my arse as it said..!!on the finer points!!..
u see it may need coupler caps,resisters etc..or as shawn said a pair of biasing diodes,plus rember to order new silcon :grease: and mica insulators for the output transistors,or all your work will be for not..
u see u go at this slowley but u will get there

ed