Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Sep Thu 19, 2019 1:26 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 12 posts ] 
Author Message
 Post subject: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Jul Sun 29, 2018 9:14 pm 
New Member

Joined: Jul Sun 29, 2018 8:33 pm
Posts: 5
Hello all, day 1 newbie to your forum but from what I see so far, this is a good place to post this in hopes of getting some help and good advice.

I inherited a Sony TC-252 from my father and grandmother a few years ago and it worked when I plugged it in. I also got several boxes of tapes with birthdays and other random family things recorded. I started listening to them and it was really good stuff like my 46 year old brother when he was 3 and audio diaries for my dad. About 2 days into digging through them I made what I know now to be a rookie mistake, and I left it idling for an entire day while I went to work. When I got home it smelled burnt as soon as I came into the room and the thing hasn't moved since. The few lights that there are do come on.

I have done a fair number of electronics repairs and I have repaired more than 50 laptops in my life so I have tools and some comfort taking things apart. I found the technicians manual for it online with schematics and took it apart. Voltmeter shows what seems to be normal voltage in several places but dies after the cap so I think I have that singled out as the problem (hopefully not just a problem). I don't know what I am doing specifically with this device though so if I have jumped the gun in thinking it is the main cap, I am all ears.

Seems like this cap is a multi voltage type cap that I could get away with replacing with just my specific voltage also (according to my limited knowledge based on what I have read so far and the advice of a guitar amp repair friend).

Disclaimer here, I have never worked with normal voltage capacitors before and have heard you can zap yourself dead if you do it exactly wrong. I am hoping someone will point this beginner at a detailed resource or lay it out for me if you have time and are so inclined. Also, I have never really grasped how to figure out which cap to use for what voltage and would love advice there to. Below is a link to pics of her all taken apart and the service manual for reference and in case it might be helpful to someone else. I am open to thoughts and advice on how to proceed and it would mean a great deal to me sentimentally to get this particular unit humming again.

Pictures of the device in question.
TC-252 Service Manual


Last edited by cranakis on Aug Wed 01, 2018 3:58 am, edited 4 times in total.

Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Jul Mon 30, 2018 1:46 pm 
Member

Joined: Nov Wed 30, 2016 7:35 pm
Posts: 4841
Location: Sunbury, Ohio 43074
Hi, and welcome to the forum. I hope we can help you here. I cannot be too specific until I see the schematic, but a few pointers for starters.

I believe what you refer to as a "multi voltage cap" is actually a multi SECTION cap, with several electrolytic caps inside one aluminum can. If so, given the age of this device, it is likely needing replacement. I doubt, however, that this component is what has burned. Possibly, but more likely it is bad, and in being bad, caused another failure, or failures, somewhere else in the amp. Hopefully your power transformer was not damaged, or some other difficult-to-find part. If this is the case, the unit should be rather simple to fix. Do NOT put power to it anymore before we nail down a few preliminaries.

While you are waiting to post the schematic, do a very thorough VISUAL inspection. I think you may find a burned out resistor or two, probably in the power supply somewhere, but easier to nail down with a schematic to go by.

As far as a capacitor (the term 'normal voltage' is not relevant,) being able to kill you, that is possible, but no more so than other lethal voltages that exist within any device that is powered by a wall outlet to say the least. Bottom line, until you learn more specifics, don't touch nuttin :)

Capacitor voltage rating (written on the cap or can) is the max the cap can handle; it does not tell you what voltage actually exists on that particular cap at any particular time.

standing by......

_________________
Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Jul Tue 31, 2018 12:01 am 
New Member

Joined: Jul Sun 29, 2018 8:33 pm
Posts: 5
Hi Barry, thank you for the response.

First, your caution is welcome and noted. I will keep it powered down.

Second some needed info:
Pictures of the device in question.

Service Manual

I gave the device another once over to look for other potentially damaged parts. It all looks better than I think it should given its age. I have a fair bit of experience hunting down burnt capacitors and other black or bubbly parts on circuit boards due to computer work I have done in the past, but nothing seems burnt, leaky, or swollen. No sign of heat damage that i can see without taking it apart further. I think some of the resistors are encapsulated in those orange square component in the last picture but I am basing that on what google searches of " psr .1+120 ohm " seem to indicate. I can provide pics in greater detail if needed.

Thank you for the help!


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Jul Tue 31, 2018 11:46 pm 
New Member

Joined: Jul Sun 29, 2018 8:33 pm
Posts: 5
Better Detail in the Photos here. I cant get a better view of the top of the audio board unfortunately without taking it much farther apart. I can if you all think I should though but the caps all look surprisingly good to my eye.


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Wed 01, 2018 1:05 am 
Member

Joined: Nov Wed 30, 2016 7:35 pm
Posts: 4841
Location: Sunbury, Ohio 43074
This is going to be extremely difficult to remotely troubleshoot. One question though.... does the deck itself work still? let's forget about the audio electronics ..... if Play, Rewind etc do not work, chances are pretty good that it has nothing to do with the circuit board.

One of the early photos showed what looked like a larger capacitor that is possibly associated with the motor, not with the audio electronics. Before digging into the board itself, let's find out if the DECK works. It appears that the caps on the board are numerous, and I'm guessing, probably still ok.

If there is a way to disconnect power to the circuit board and still see if the deck/motors work, that's preferable but if not, I guess you'll have to risk full power test. I'm wondering if the motor itself is what may have overheated.

_________________
Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Wed 01, 2018 3:53 am 
New Member

Joined: Jul Sun 29, 2018 8:33 pm
Posts: 5
Don't worry Barry. I have been staring at this for awhile trying to get the will up to take the project on so I have a starting point. I think you are going to be pleasantly surprised by what I discovered (I think) while digging into this. The below image is from page 17/18 of the manual (12 of the PDF). Unless I am looking at it wrong or missing something, the power from the wall goes to the main cap and motor immediately. Since I get no motion from the motor, I think this means the issue is the cap, the motor, or the fuse, or the encapsulated doo-dad. I get an ohms reading across the fuse and the orange box encapsulated doo-dads (S302 and S301 (I think)in the pic below) so I think they are likely good.

Image

I don't know what C302 is but that or the Cap I think are the problem. What do you think about replacing the cap and see where that takes us? Also, am I reading that wiring diagram correctly? I have a volt meter if you want me to test anything somewhere along the path.

Edit: I forgot to answer your question. Audio was good on it prior to it burning out. There were some speed issues but I think those seem likely motor or power related too. It would play even the day before the "burn out." It went from working fine to no movement. I thought it was a belt that had broken before i realized there were no belts.


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Wed 01, 2018 5:00 am 
Member

Joined: Nov Wed 30, 2016 7:35 pm
Posts: 4841
Location: Sunbury, Ohio 43074
C302 is a pair of capacitors that, if I am reading this right, are just paralleled to provide the proper 1.5uF. It appears to be a "motor run" capacitor ... which in the world of motors, means it is needed for the motor to run. So, the cap could be bad. If you want to try substituting it, first disconnect it and then put your sub in. You can try testing it by disconnecting it, and using your ohmmeter at low ohms scale. When you put your ohmmeter leads across it (discharge the cap first please) the meter should "kick". If not, it's open.

See if you can detect that "burning aroma" in the motor, with the power off. No need to risk blowing your nose off. If the cap went bad, it's likely the motor may have as well but perhaps all is still well there.

It looks like the other "potted doohickey" thingies are a resistor and cap packaged together, that are supposed to stop the switches from arcing when they are switched on or off. If they are shorted, the switch would think it's "ON" all the time, although at 120 ohms, so probably eventually the doohickey would open anyway eventually. If they are open, the switch could arc when opening or closing. Either way, the unit should basically still work.

A replacement cap for C302 could be a single one at the indicated value and voltage, or a pair of them paralleled to do the same. Remember when paralleling two capacitors, you double the value but half the working voltage. So to get a cap with a total of 1.5uF you could parallel two 0.75uF ones. They'd have to be at least 500VAC capacitors each to provide the indicated spec of 250VAC. Or you could buy one 1.5uF capacitor at 250VAC. rated for motors. Caps rated in DC instead of AC won't be good enough for this application.

I'd not try replacing it with a plain old "film" capacitor... stick to one that is designed for "motor run" usage. They are available, either new or old stock. Motor run caps are a special breed.

_________________
Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Wed 01, 2018 11:24 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 14716
Location: Fernandina Beach, FL
The circled capacitor is the motor run capacitor. I have worked on several Sony TC-630 decks and found these to be a problem. However, these decks are now about 50 years old. In some cases, the capacitor exploded and spewed a waxy substance all over the inside of the deck. Symptoms could be no run or slown run of the motor and excessive heating of the motor. It is important that if the capacitor is replaced, you must use the exact value of the original. Higher capacitance is not an option.

_________________
Don


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Wed 01, 2018 5:01 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1792
Location: 07450, New Jersey
It looks to me like the motor actually requires 2uf to run. 1.5uf + .5uf, the two sections wired in parallel.

_________________
Tim

"One of the advantages of being disorderly is that one is constantly making exciting discoveries." A. A. Milne


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Wed 01, 2018 5:19 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 14716
Location: Fernandina Beach, FL
Tim wrote:
It looks to me like the motor actually requires 2uf to run. 1.5uf + .5uf, the two sections wired in parallel.

Tim, I think that you are correct. I saw various versions of the TC-630/D. If I remember correctly, the International version had the same motor run capacitor and the USA only version had only a single section capacitor.

_________________
Don


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Wed 01, 2018 5:35 pm 
Member

Joined: Nov Wed 30, 2016 7:35 pm
Posts: 4841
Location: Sunbury, Ohio 43074
Thanks Tim. Looks like my antique eyeballs missed that. Good catch

_________________
Preserving the hist. of electronics, one boat anchor at a time! :)
https://www.bbtvtestequipment.com


Top
 Profile  
 
 Post subject: Re: Reel to Reel - Sony TC-252 - Capacitor Replacement Help
PostPosted: Aug Fri 03, 2018 3:28 am 
New Member

Joined: Jul Sun 29, 2018 8:33 pm
Posts: 5
How does the Voltage Selector Socket from that diagram work? I see a C there in the center. Does that mean "common?" I am going to take the capacitor up and cut into that wax/plastic seal where the wires are entering. I will discharge the cap before taking things apart. I will get some pictures and share.

Looking at the physical wiring vs the diagram; It looks like the wires from the main power (through the switch) go into the cap housing. On the diagram they go into the voltage socket selector so I am guessing that is on top of or inside the can of the main cap (see pictures in the link at the end of my original post). The orange wire going into the wax/plastic of the main cap is the main power from the switch. The dark grey wire from the same main switch is the one going to the fuse (~f in the diagram).

Orange wire I am talking about is indicated below:
Image


Top
 Profile  
 
Post New Topic Post Reply  [ 12 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: Google [Bot] and 5 guests



Search for:
Jump to:  




























Privacy Policy :: Powered by phpBB