Sony HP-310 motorboat

[David Corbin]

Hello, I am new to this forum, new to troubleshooting stereos, and fairly green when it comes to tracking stuff out. That being said I can usually take most gaming things apart, diagnose the problem and get it working. Where I am having trouble is like jheu02 had with his Sony 6046a. I got motorboating and was told to just change out the transistors. Changed out with the same 2sc1060 transistors but did fix theproblem.
To make matters worse, I heard a pop and the fuse blew. Didnt have a 125v 6A fuse so had to use a 250v 6A fuse. When i got everything put back the way it was, I started seeing smoke from the two diodes on the power board. I have recently changed them for what I could tell are the same r3000 diodes. Once i got it all back together again, I checked for any short and two of my transistors are showing continuity with a ground screw which I believe that means they are both shorted and what could have caused the diodes to blow. I also found two R/C filters (one on the power switch and the other on the power board) with the same values to be bulged and bad as well. The value of the RC is .033uF 120 ohm 500V. Is a .1uF 120 ohm 500V a good replacement because I cannot find an exact anywhere.
Any advice for a noob would be much appreciated because I just want to get this 1973 machine going again. I posted the same message in the home theater portion by mistake. Thank you in advance.

 

[avionic]

Welcome to AK Dave from another Dave.

Changed out with the same 2sc1060 transistors but did fix the problem.

Where did you get the transistors?

 

[avionic]

I checked for any short and two of my transistors are showing continuity with a ground screw

Post a photo...please..

 

[David Corbin]

I will open it up tomorrow and post a pic of the inside...I think I have fixed the short but that is with taking the RC filter that was bulged off the power switch...Here is a pic of the RC that I pulled off the power switch...the one on the power board looks exactly like this and is bulged as well...

 

[David Corbin]

Forgot to say I got the transistors off ebay...they said they were NOS Hitachi 2sc1060...these are the ones I bought...the ones I replaced only say 1060 3L on them, but I did as much research as I could to make sure they were exactly the same...

 

[avionic]

. Is a .1uF 120 ohm 500V a good replacement

Probably as close as your going to get..

 

[avionic]

two of my transistors are showing continuity with a ground screw

Are you refering to the mounting screw on the TO-220 transistor? Because the metal tab of the transistor is directly connected to the center pin of the transistor ie. collector pin

 

[David Corbin]

No...as the transistor sits with the legs on top, the left leg of the two middle transistors show continuity when I put the negative lead on a ground screw and the positive lead on the left leg on both middle transistors...

 

[David Corbin]

And when I mean ground screw...I mean one that goes into the chaise or one of the screws holding down the transformer...not the screws on the transistor themselves...and the only time it shows continuity like that is when the power cord is hooked up to that board...if I unplug that cord it doesn't show continuity anymore, so I assume that is a normal thing...btw the new diodes didnt smoke after I removed that RC filter from the power switch, but I didnt leave it on long enough to really test it because i dont have enough diodes to change out right now...

 

[avionic]

No...as the transistor sits with the legs on top, the left leg of the two middle transistors show continuity when I put the negative lead on a ground screw and the positive lead on the left leg on both middle transistors...

Don't suppose you have a schematic? Do you?

 

[David Corbin]

I will be getting one sent to me next Thursday...you know what a pain that is it seems with having to wait for next payday in the military...I am getting it from stereomanuals.com

 

[avionic]

What branch of the service. In your avatar it looks like Army or Marine BDU. Thanks for your service..

 

[David Corbin]

Nah that's haze gray and blue brother...I am a Navy flight officer...I fly in the E-6 Mercury stationed at Tinker AFB...That pic I was stationed on the Nimitz as a "shooter", launching planes off the pointy end...

 

[David Corbin]

Would those two RCs be causing the motorboat effect...I got it to go away for a little bit by removing the right most screw and plate but that took away the right channel and I had both speakers running off the left channel...then the other day it started on the left channel as well...couldnt get it to go away this time...volume lever doesn't effect the tone of the motorboating and it is just that steady 1 sec heartbeat like pulse...thanks for all the responses so far btw...

 

[avionic]

Tinker-- Oklahoma City .. I was at Eglin AFB,Bitburg AB and Keflavik NAS.

 

[avionic]

Would those two RCs be causing the motorboat effect...I got it to go away for a little bit by removing the right most screw and plate but that took away the right channel and I had both speakers running off the left channel...then the other day it started on the left channel as well...couldnt get it to go away this time...volume lever doesn't effect the tone of the motorboating and it is just that steady 1 sec heartbeat like pulse...thanks for all the responses so far btw...

I suppose its a possibility..I will reserve judgement until I can see a schematic.

 

[David Corbin]

Alright I will post when I get it in about a week or so...thanks again for the help...

 

[David Corbin]

So I dont think my problem is actually motorboating. It is more like a steady pulse once power is applied to the unit. It is like a steady thump or whomp if you will. I am looking into replacing the two RC filters I found messed blown, but wondering if anyone has heard this type of rhythmic sound.

 

[David Corbin]

So I got it back to the state before I fried some stuff...the heartbeat came back but twisted a screw on one transistor, and the whole left channel went out...tightened it back some but heartbeat didnt come back but neither did the left channel...I have no idea what could be wrong

 

[David Corbin]

Here are some pics of the inside...I had some different smoke that I cant duplicate now...a couple of the pads got super hot...now they dont and the left channel is still out...