View Full Version : Capacitor Brand Recommendation For STA-2100D Rebuild


69sixpackbee
11-26-2012, 02:11 AM
Hi, folks,
Now that I have my Pioneer SX-1250 up and running, it's time to dive into my Realistic STA-2100D. I want to do a total recap of this baby and am looking for some recommendations for caps. My Pioneer was done primarily with Panasonic EEU caps and UPW/UKL Nichicons. Is it advisable to go this same route? Is there a "rule of thumb" with cap types in the signal path as opposed to the PS side of it?
This particular receiver has a very weak stereo signal which seems to be inherent with failing "D" units as it is associated with the MPX/Dolby board. I have two of these receivers with the exact same issues. I get a very weak FM stereo broadcast and the indicator will just flicker and the tuning meter barely moves. Otherwise, the amp section really kicks butt!

Thanx in advance for the help
Bud

sony6060
11-26-2012, 03:17 AM
I prefer CDE 380LX or 381LX in the main power supply. The main PS caps do have a slight sonic signature, the CDE are smooth sounding IMO.

Binkman
11-26-2012, 07:40 AM
If the amp 'kicks' butt, leave it alone. As for the tuner reception, are you using a 300 ohm dipole antenna? You won't get to first base without one. Might consider a FM signal booster depending where you are. If the antenna doesn't solve the issue then the tuner probably needs to be aligned.

Most of the realistic battle ship receivers were designed for distance reception and included fm mute, Auto M, and high mpx. and those features required a mast antenna or good elevation. e.g. my sta-2300

69sixpackbee
11-26-2012, 11:26 AM
If the amp 'kicks' butt, leave it alone. As for the tuner reception, are you using a 300 ohm dipole antenna? You won't get to first base without one. Might consider a FM signal booster depending where you are. If the antenna doesn't solve the issue then the tuner probably needs to be aligned.

Most of the realistic battle ship receivers were designed for distance reception and included fm mute, Auto M, and high mpx. and those features required a mast antenna or good elevation. e.g. my sta-2300

Well, I am more than certain the tuner has issues. I live about 35 miles from Los Angeles and any type of reception is never a problem. in fact, I rarely ever have to use any type of external antenna to pick up anything on my gear. Yes, I have tried with a good amplified antenna as well as the one on my roof and without success so it is definately a problem with the FM tuner. I have seen quite a few of these "D" units and all of them suffer the same malady once they start getting old. I know when they ARE working right they have one of the best multi-gang tuners in most any receiver. I will start capping this beast and then visit the tuner section later.

Thanx,
Bud

Binkman
11-26-2012, 11:43 AM
I don't understand why you'd recap the amplifier if there is nothing wrong with it?

69sixpackbee
11-26-2012, 12:24 PM
Primarily for good measure. It's a known fact the the caps start to dry up and lose their ESR over time so being that this receiver is over 30 it's a good time to do it. Parts are cheap and the time it takes to do it is not a lot ( if you have the equipment....I do) so I like to keep them freshened up.



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rcs16
11-26-2012, 02:07 PM
This particular receiver has a very weak stereo signal which seems to be inherent with failing "D" units as it is associated with the MPX/Dolby board. I have two of these receivers with the exact same issues. I get a very weak FM stereo broadcast and the indicator will just flicker and the tuning meter barely moves.
Not sure how you can determine that the above problem is associated with an ecap. Probably need to do a bit more troubleshooting to determine the cause. A weak signal, as indicated by the low tuning/signal meter is saying this to you and as a result you get weak stereo reception. Need to check if your antenna signal is not the problem source.
Regards Rick

69sixpackbee
11-27-2012, 05:05 PM
I'm going to just do a quick check of the tuner circuit but I know this unit is tired. I am not going to spend a bunch of time trying to sort it out until i get this thing up and running with the proper voltages. The bias is unstable as hell on one side and the relay jumps in and out of protection. The LH heat sink warms up REAL fast and then it settles back down. It has some issues for certain. On another one I have the voltages are spot on and it sounds awesome but here again, I get no stereo separation and just barely a wiggle on the signal strength meter even hooked up to a good amplified antenna. They BOTH pull in every station under the sun but not in stereo.

I love these RS units but they seem to be buggy in that section. I have seen personally at least three more 2100D's that all exhibit this same characteristic.

I dunno...looks like a challenge.:tears:

Houas07tc
11-28-2012, 05:18 AM
I was googling and found this

http://tech.juaneda.com/en/articles/electrolyticcapacitors.html

69sixpackbee
11-29-2012, 07:41 PM
Well, I have been trying, albeit a bit feebly, to formulate a cap list for this receiver. I have read so many white papers, articles, ramblings about "use these and forget those" posts that my noggin is on overload! I got some really good insight from some fellow AK'er's on selection as well and, not suprizingly, they differ in opinion as well, so I am going to throw this out and see if it makes sense to you much more experienced than I. I have broken down the parts list from the repair manual in sections. I.e; power supply, main amp,..etc. I then started circling just the electrolytics in the list that are associated with the respective section/board. Anything 25V and lower I figure it being anything in the audio path and anything above is associated with the power side of it. Anything less than 1uF I have been sizing up stacked film caps. I'm still not sure about the tant's and exactly which ones I do need to focus on. There are just a few of those.

I have been trying to find caps above 25V in the Panasonic FM/FC series or Nichicon HE's. I like the Silmic II's in the lower voltages but the selection is still kinda slim. I've been mixing them in with Nichicon KL's.

Am I on the right path here? Do my choices seem on par with the general consensus?
This is my first attempt at trying to formulate a list so all help and constructive criticism is appreciated.

Thanx,
Bud

Binkman
11-29-2012, 08:03 PM
Will these help?

http://www.analogmetric.com/category.php?id=154

costellom5
11-30-2012, 09:33 AM
Leaving aside the tuner,I would go with 105C caps in the power supply,and the rest "audio grade".A well known brand should be all you need.

69sixpackbee
11-30-2012, 12:32 PM
One more question.
This has a separate multi-gang tuning capacitor on a separate board with a few coils and trimmers. Then there is the bigger IF/Dolby board with 17 lytics and three tants as well. Is it prudent to swap these out? Is this considered to be in the "tuner" section? I am not real concerned either way as I am going to be sending this off to Mike at Radio X Tuners for a re-alignment.

Thanx!

Bud