Another thread on Capacitors...

[Lasonic TRC-920]

Like you guys, I have been following the thread "Fixing a Legend" which is a subject that has been on my mind...

The radio in question is my Lasonic TRC-975. It sounds good, it hits hard, but next to my TRC-935 it's a weakling.

With the LBS off and the 975 set to 75% volume, it is as loud as the 935 at 40-45%. I have had both of these radio's for a few years now and with everyone's comments about the 975, I just can't imagine this is it for the 975.

So, a few months ago I started thinking....MAYBE THE 975 NEEDS CAPS

Some questions:

If the Capacitors are dry, drying or dried out does the unit still work?

Does the volume start to lessen like I am experiencing?

The phrase "motorboating" was used in the other thread, but I'm not experiencing anything like that.

Do you think this radio would benefit from a recap?

 

[blu_fuz]

That's a good question. Ill have to compare my 975 and 935 with eachother again to see if it helps you decide what might be wrong with yours if anything.....

 

[Lasonic TRC-920]

That's a good question. Ill have to compare my 975 and 935 with eachother again to see if it helps you decide what might be wrong with yours if anything.....

Thanks....I find the 951 and 935 to be closer in volume with the 975 coming in last

I'll be following your thread as well, see where it goes

 

[jimmyjimmy19702010]

Whilst I don't have multiples of any boxes to do side by side comparisons, some of my boxes definately have needed re-capping.

The symptoms of a box with problematic capacitors will vary depending on the design of circuitry and the function of the actual capacitors affected as not all capicitors for various reasons, 'age' at the same rate.

An example would be my Hitachi TRK-9300. This unit had issues which included: a flat sound with little treble, unbalanced Left and Right channel output and distortion developing at only low to medium volume levels.

I replaced all internal electrolitic capacitors (minus tuner board).

Immediately upon powering up the unit after surgery, I noticed a huge leap in the treble levels. I also noticed that I could set the equaliser at max bass levels and crank it without immediate distortion kicking in.

I guess it depends of the quality/design of unit when manufactured as to how dramatic a difference a re-cap would make though.

Some units, like my M9998K a just too daunting a project for a novice, due to the complexity of construction.

I think the vast majority of members boxes would benefit from a re-cap - although to vastly differing degrees.

On an easy box to work on, like the later Panasonics, it can be a fun project. And as long as you don't mix capacitor polarities etc, I think you will pleasantly surprised by the performance upgrade/restoration that may be offered by a re-cap.

James...

 

[Lasonic TRC-920]

Whilst I don't have multiples of any boxes to do side by side comparisons, some of my boxes definately have needed re-capping.

The symptoms of a box with problematic capacitors will vary depending on the design of circuitry and the function of actual capacitors affected as not all capicitors 'age' at the same rate.

An example would be my Hitachi TRK-9300. This unit had issues that included: a flat sound with little treble, unbalanced Left and Right channel output and distortion developing at only low to medium volume levels.

I replaced all internal electrolitic capacitors (minus tuner board).

Immediately upon powering up the unit after surgery, I noticed a hugd leap in the treble levels. I also noticed that I could set the equaliser at max bass levels and crank it without immediate distortion kicking in.

I guess it depends of the quality/design of unit when manufactured as to how dramatic a difference a re-cap would make.

Some units, like my M9998K a just too daunting a project due to the complexity of construnction.

I think the vast majority of members boxes would benefit from a re-cap - although to vastly differing degrees.

On a easy box to work on, like the later Panasonics, it's a fun project. And as long as you don't mix capacitor polarites rtc, I think you will pleasantly surprised by the performance upgrade/restoration.

James...

OK, That sounds promising....and the 975 is so simple to work on....I think I will open it up and take a quick inventory to see what I'm really looking at.

Thanks James

 

[k2j]

Good post. I also have replaced caps on a few of mine with noticeable improvement. Did the amp and Power supply board on both occasions. The power supply section is needed as the AC gets filtered or cleaned with electrolytics and you want that to be good clean power. The amp board is a good one too for obvious reasons.. I didn't bother with the tuner board.

 

[Lasonic TRC-920]

Good post. I also have replaced caps on a few of mine with noticeable improvement. Did the amp and Power supply board on both occasions. The power supply section is needed as the AC gets filtered or cleaned with electrolytics and you want that to be good clean power. The amp board is a good one too for obvious reasons.. I didn't bother with the tuner board.

Interesting, I didn't know about the power supply. I will have a look at that as well and count them up too.

 

[BoomboxLover48]

I have tube radios made in 1965 with electrolytic caps still reading good and the radio sounding fantastic. I do have 6 Philips high end tube radios with their original electrolytic caps still workimg FINE!
It all has to do with the capacitor brands, how the equipment was stored (storage / environment conditions) and all.
I only changed caps on radios like SABA made in Germany when friends advised me to do a full replacement.

In the 80s they made very good electrolytic caps.

No matter what how well they were made or not, if you operate them in worst weather conditions they all can go bad...

Hi Fi electronic equipment are not meant to be operated or stored in severe weather conditions...and only in A/C rooms with humidity control with dust control.