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-   -   Panasonic AG-1980 capacitor repair? (http://www.digitalfaq.com/forum/vcr-repair/5166-panasonic-ag-1980-a.html)

kpmedia 08-04-2013 09:36 PM

When you figure out what's wrong, let us know. :)

videonut 11-18-2013 09:52 AM

I just finished to replace all electrolytic caps on this unit and it works amazing. What Rumburarski said is very true. On this Y/C card replace them all. Some were still ok but since about half of them had readings off the chart I changed them all. Can be done with a thin tip iron but be very carefully to not damage the board. Probably hot air and tweezers are better choices. Takes time and concentration. I did NOT have any problems with the picture before . Once the caps replaced, the colors were vivid and I think it makes a big difference. I also want to mention that I found on the main board one capacitor at 47uf and probably 16V (not sure) that was electrolytic but on the board I did not see indicated any polarity ..... . It does not make sense. Anybody any thoughts.
Thanks.

rumburaski 11-18-2013 10:07 AM

Congratulations Videonut! For changing all the caps. Well, if the electrolytic does not indicate any polarity than it is non-polar. If this is out of specs I would replace it with same.

lordsmurf 11-18-2013 10:12 AM

I'm reading this with great interest. :)

Yet, sadly, I don't know if I could ever do something like this myself, especially given my unsteadiness due to medical issue of the past years. (I do hope, however, that I fully regain my dexterity in the future.)

If you're interested in doing this for others, you could make a few bucks for sure. Interested? We've always on the lookout for responsible (non-scam, non-slow) people that can do this for others. Most people are not skilled with re-soldering capacitors. Even non-amateurs video folks like myself!

LSI DVD recorders have caps issues, too, and must be replaced (JVC, Panasonic).

rumburaski 11-18-2013 10:46 AM

$75 complete recap (aluminum cans). Bad IC's? (black and white or blue screen) additionally $55. If bad IC's are suspected, must ship whole unit. Client to pay shipping both ways.

NJRoadfan 11-18-2013 11:22 AM

Quote:

Originally Posted by lordsmurf (Post 28975)
If you're interested in doing this for others, you could make a few bucks for sure. Interested? We've always on the lookout for responsible (non-scam, non-slow) people that can do this for others. Most people are not skilled with re-soldering capacitors. Even non-amateurs video folks like myself!

I have a contact that I contracted work out to in the past. The work was top notch and prices reasonable. He primarily does computer equipment, but something like the Y/C board posted above is no problem. He does charge more though since there are more caps to replace.

I have attempted SMD cap replacement in the past. I landed up using wire cutters to remove the old caps. Usually the body of the cap pulls out leaving the legs on the PCB. From there you can add remove the legs without too much risk of lifting a pad.

Has anyone tried replacing electrolytics with ceramic or solid polymer caps? They should last a lot longer, but in some cases cause problems in circuits. Tantalum caps will work too, but I don't trust them since their mode of failure usually involves blowing up!

rumburaski 11-18-2013 11:54 AM

I also read somewhere (not here), people are substituting non polar for polar electrolytics and vice versa. I cannot comment on this because I never tried and perhaps never will. Wire cutters are never a good idea to remove smd caps or smd ic's, unless you have time (and funds) on your hand fixing broken pads.

videonut 11-18-2013 12:23 PM

I do not use wire cutters, so I do not understand your comment. I used just a simple iron station with the temp at 350C and a lot of concentration and detailed work. Everybody please be advised not to even try to solder if you do not know how to do it because it is very dangerous. Actually nobody should ever attempt to do a job that can be done by a professional.
The caps were the original ones, plus the values shown in the service manual are sometimes different. Why is it that way I do not know. Actually there were a couple of BP caps that I could not find. What would be a proper replacement for a BP electrolytic cap in your opinion?
Those caps you mention in your post I also found to be problematic from the beginning.
Thanks for for your help.

rumburaski 11-18-2013 12:49 PM

Quote:

Originally Posted by videonut (Post 28981)
I do not use wire cutters, so I do not understand your comment. I used just a simple iron station with the temp at 350C and a lot of concentration and detailed work. Everybody please be advised not to even try to solder if you do not know how to do it because it is very dangerous. Actually nobody should ever attempt to do a job that can be done by a professional.
The caps were the original ones, plus the values shown in the service manual are sometimes different. Why is it that way I do not know. Actually there were a couple of BP caps that I could not find. What would be a proper replacement for a BP electrolytic cap in your opinion?
Those caps you mention in your post I also found to be problematic from the beginning.
Thanks for for your help.

Please do not feel offended if i did not understand "landed up". Does "landed up" means "giving up"? Also, I see BP caps available for purchase and in a variety of values. I don't understand why would I be looking for a "replacement", when I can put back what came out. To answer you question, Yes. There are several youtube videos showing how to make BP out of two identical polarized caps. It also depends upon where in the circuit will those "make ups" be used. From my end I can see that is not recommended in smps or dry vs. wet electrolytics. "In general, this sort of trick should be considered a last resort. Since bipolar capacitors are usually needed for signals, it can often be arranged to require a lower bipolar capacitance. Multi-layer ceramic caps have advanced significantly in the last decade. If you can make do with 10 uF instead of 100s of uF, a ceramic can can probably do the job".
http://electronics.stackexchange.com...r-electrolytic

NJRoadfan 11-18-2013 01:42 PM

Quote:

Originally Posted by videonut (Post 28981)
Everybody please be advised not to even try to solder if you do not know how to do it because it is very dangerous. Actually nobody should ever attempt to do a job that can be done by a professional.

Soldering, like most things requires practice and common sense. I'm run across many "professionals" that I will never let near any of my equipment due to their shoddy work.

Quote:

The caps were the original ones, plus the values shown in the service manual are sometimes different. Why is it that way I do not know. Actually there were a couple of BP caps that I could not find. What would be a proper replacement for a BP electrolytic cap in your opinion?
Those caps you mention in your post I also found to be problematic from the beginning.
Thanks for for your help.
All ceramic caps are bipolar by design. I had no problem finding bipolar SMD electrolytic caps either.

Quote:

I also read somewhere (not here), people are substituting non polar for polar electrolytics and vice versa. I cannot comment on this because I never tried and perhaps never will. Wire cutters are never a good idea to remove smd caps or smd ic's, unless you have time (and funds) on your hand fixing broken pads.
Non-polarized can replace polarized without a problem. As for the wire cutters, I was a skeptic, but it worked. I wouldn't try it with ICs, just SMD caps. Its a lot easier to remove the legs when the cap and plastic body aren't on top of it!

rumburaski 11-18-2013 01:56 PM

Quote:

Non-polarized can replace polarized without a problem. As for the wire cutters, I was a skeptic, but it worked. I wouldn't try it with ICs, just SMD caps. Its a lot easier to remove the legs when the cap and plastic body aren't on top of it!
The problem I am having with non-polarized caps are that they are not cost effective. Also, I recently worked on a jvc board. The JVC pcb can't take any kind a wiggling. In this rare instance I use hot air.

volksjager 11-18-2013 03:43 PM

Quote:

Originally Posted by rumburaski (Post 28977)
$75 complete recap (aluminum cans). Bad IC's? (black and white or blue screen) additionally $55. If bad IC's are suspected, must ship whole unit. Client to pay shipping both ways.

where are you located?

is it possible to replace the electrolytics with solid caps? if not at least better electrolytics?

rumburaski 11-19-2013 06:16 AM

Quote:

Originally Posted by volksjager (Post 28986)
where are you located?

is it possible to replace the electrolytics with solid caps? if not at least better electrolytics?

I am located in New Jersey.

$75 cheap Chinese, tested, low esr, sometimes lower esr than Nichicon
$95 Nichicon caps

All caps are tested for low esr. 30 days warranty on all work performed. Regular electrolytics are more rugged than smd caps. In real life situation I compared the two brands and I haven't seen benefits of using Nichicon vs. Chinese. But if you insist of me using Nichicon (or other brand), I could do it. Bear in mind you are paying for 26 new caps plus complete labor. I think $95 is a small price to pay.

videonut 11-19-2013 09:25 AM

Well let me rephrase the question I had. Apparently I get replies to things I never said and questions I did not ask. I mentioned that on the MAIN board I noticed one electrolytic capacitor at 47uf 6.3V that on the MAIN board is marked as bipolar. It is locate somewhere in the front left area. I also mentioned that there are few more bipolar caps and I could not find something to replace them. This are not SMD caps. The question was how to handle those bipolar/non polar caps. Any ideas?

Now about the Y/C card: I changed only the aluminium electrolytic caps. Apparently there also SMD tantalum caps, correct me if I am wrong, and there are a lot of them. Good luck replacing them ( much more than 26 total).
I did replace the caps in this unit for myself only and took me about a week. I am sure there are people doing this for living. I would go with good brand name caps with long life. Low esr today and high esr few months later is not what I would look for. Low ESR and very high quality series caps equals very expensive.

On ebay those fixed units are probably only partly fixed, or fixed to work for a while ( for how long my guess is your guess). I could have change some of the caps in the power source and front panel, including the ones located next to the display and the funny noises disappear and the display is much better (NOT like new). But when I checked more components I realized that it needed a complete overhaul and this turned out to be very expensive. Of course this assuming the heads and the gears are still in good shape.....

About the mechanical part I can say it is very solid with the exception of some plastic gears and one small bolt that can give up. And yes do not attempt to take it appart because if you are out of alignment it will start acting funny. Is there any manual about alignment, just curious.

To me this was an expensive overhaul and I count only for the parts, but the result is sweet.
Good luck to everybody.
Nice forum.

rumburaski 11-19-2013 09:54 AM

Here is a start videonut http://www.mouser.com/ProductDetail/...t3hgt2nysJs%3d

NJRoadfan 11-19-2013 10:41 AM

Leave the tantalum caps alone, they are usually fine. The price difference between no-name and quality electrolytic is minimal. The price goes up substantially if you want ceramic or polymer replacements.

videonut 11-19-2013 01:29 PM

Themouser is so and so in regards to prices and do not have everything. Not my cup of tee, but thanks. The tantalum caps are really small and expect to last longer too. The no-name brands caps I do not prefer, to me is like playing roulette, some are good, many are garbage, but if you used some and you had good results, you know better. If you noticed the most sensitive components are always using brand name caps,unless is a cheap made product.
On a different note, what is a good lubricant that you guys use on this units?
Thanks again.

rumburaski 11-19-2013 01:36 PM

Quote:

Originally Posted by videonut (Post 28998)
Themouser is so and so in regards to prices and do not have everything. Not my cup of tee, but thanks. The tantalum caps are really small and expect to last longer too. The no-name brands caps I do not prefer, to me is like playing roulette, some are good, many are garbage, but if you used some and you had good results, you know better. If you noticed the most sensitive components are always using brand name caps,unless is a cheap made product.
On a different note, what is a good lubricant that you guys use on this units?
Thanks again.

Molytone grease 265 (mor265) Sumico Lubricant

kpmedia 11-19-2013 02:56 PM

Quote:

Originally Posted by rumburaski (Post 28992)
I am located in New Jersey.

$75 cheap Chinese, tested, low esr, sometimes lower esr than Nichicon
$95 Nichicon caps

All caps are tested for low esr. 30 days warranty on all work performed. Regular electrolytics are more rugged than smd caps. In real life situation I compared the two brands and I haven't seen benefits of using Nichicon vs. Chinese. But if you insist of me using Nichicon (or other brand), I could do it. Bear in mind you are paying for 26 new caps plus complete labor. I think $95 is a small price to pay.

I've added this: http://www.digitalfaq.com/forum/vcr-...html#post29001

Nice to have another solid option. :congrats:

And replacing crappier caps with better caps is EXACTLY what I want to see more of. So many shops seemingly refuse to do this, and I often wonder if it's because of a limited understand of electronics.

Argalby 03-04-2014 05:14 PM

I just wanted to post back about how the repair to my AG-1980's went. All I can say is it's much akin to brain surgery~ I got both of my units going but it's extremely tricky. You need to replace all the SMD aluminum caps in the video board. You need to be proficient in the use of a hot air rework station. Every now and again you're going to accidentally melt part of a connector, or blow a 2mm wide mini smd capacitor off the board. This isn't a repair for those feint of heart. It's about a 3hr job. You'll probably have about $30 in parts plus a rework station and other odds and ends, plus a bottle of scotch :)
By the way, in my experience, it just doesn't work trying to repair these SMD caps with a regular soldering iron, you just can't get in at the small connections. You can't get a good solder joint. Even getting the video board free from the main circuit board is tricky. The Ag-1980 is a very nasty, tricky, persnickety machine!

So all in all I got my unit back to good health and have another one ready to sell. The Big Reward is the happiness when you pop in a tape and see the glorious picture that these units give! It's worth the trouble and/or cost of repairs!


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