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#1 caution

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Posted 21 December 2014 - 03:06 AM

I've found some sage advice on the process of recapping itself, but nothing specific for the C100. I'd be interested in a list of electrolytics worth replacing and even better, which of those could afford to be audio grade.



#2 jimmyjimmy19702010

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Posted 22 December 2014 - 03:15 AM

I'd replace them all minus the ones on the tuner board - they are all over due for replacement anyway.
You're helping protect the rest of the other components in the process so it's a good idea.

Have a capacitance meter on hand too so you can check each cap as you remove them from the circuit. I always take note of any caps that are way out of spec

And don't skimp on the quality of the caps - it's not worth the risk on a C100 IMHO.

Have fun,

James.... :-)

#3 caution

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Posted 04 March 2015 - 11:49 AM

Oh I am having tons o' fun. Thanks for the info. Just curious why fresh electrolytics on the tuner board is a no-no,  I'm already having issues with reception as it is, I'd think this could only help.



#4 Superduper

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Posted 04 March 2015 - 12:00 PM

You can replace the electrolytics on the tuner. It's the Styrol ones you don't want to touch as they might affect alignment. Speaking of which, replacing the electrolytics will not likely improve reception. That's more likely an alignment issue or weakening RF/IF amp stages.

#5 caution

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Posted 07 March 2015 - 02:15 PM

Yeah, I saw Retro Addict suggesting VR001, will try that. I did a full breakdown of all the cans in the unit and went with the Nichicon Gold for everything. Digikey had every value, but not the Panasonic FCs. Although it did run a little more going all Nichicon, I have no schematic to ensure I'm only using them in audo paths and Panasonics everywhere else. And like you had mentioned, the large caps on the HA1392 outputs (which this has) are in the audio path (the C100 has 2200uF instead of 1000uF) so you can't judge based on size.

 

Speaking of schematics, what are the chances we'll ever see one here? I already drew the LED boards and could do more if you think it would benefit the community at large. At the very least I could put together a wiring diagram with all of the notes I've got now, that may help the most.



#6 Superduper

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Posted 07 March 2015 - 04:36 PM

Conion did something totally unique with their HA1392 configuration.  It's not uncommon to have bridged HA1392's (Hitachi does does not show a bridged configuration in their recommended application sample schematic).  One application that comes to mind is the Pioneer SK-900 which also uses these chips in Bridge configuration.

 

What IS unique however is Conion's use of output capacitors.  In almost every bridged application I've observed, the output caps (that might've been used in SE configuration) were not used.  Apparently, Conion's amp design works but certainly isn't conventional. 

 

Unless you were able to draw the entire schematic (a mean feat and huge undertaking), I hardly doubt it will be of huge benefit, and even worse if there is any ommissions and errors.  There aren't that many members here who could really use one anyhow.  On the other hand, a proper Point to Point block wiring diagram would help most of the members due to the huge number of similar sized interchangeable connectors which can cause confusion, especially if any gets disconnected.  Properly disconnecting and reconnecting everything on this model is a huge pain in the buttocks.



#7 JVC Floyd

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Posted 07 March 2015 - 04:38 PM

i used paint pens to color code the plugs on the c100 , just put a dab on the plug and where each plug goes and take pics for insurance.



#8 Superduper

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Posted 07 March 2015 - 05:17 PM

Yep, I do that too with sharpies and also use tape to label the wires.  But there's like 30 of them and in the course of working on them, it's not unusual for the labels to fall off, or the painted/sharpied marks to suddenly disappear after exposure to solvents like IPA or deoxit.  Also, using paint pens is like trying to paint eyelashes using fat brushes on those 1/64th scale model people since those small black connectors are the size of pea heads.



#9 toshik

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Posted 07 March 2015 - 08:55 PM

IMHO it's a waste of time, labor and money to replace ALL caps. All you'd need to check is the power supply filtering ones and faulty bypasses. Also you might as well do a visual inspection for leaky ones.



#10 Superduper

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Posted 07 March 2015 - 10:51 PM

IMHO it's a waste of time, labor and money to replace ALL caps. All you'd need to check is the power supply filtering ones and faulty bypasses. Also you might as well do a visual inspection for leaky ones.

Yeah.  Sure.  Ok.



#11 jimmyjimmy19702010

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Posted 08 March 2015 - 03:39 AM

I completely recapped a Hitachi TRK-9300 a while back. Every cap looked perfect visually but most were out of spec. After replacing all the electrolytic caps (minus the tuner board), the difference it made to the performance of the unit was amazing.

I'm just about to recap my 32 year old National RX-C45. Caps don't last forever.

James.... :-)

#12 toshik

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Posted 08 March 2015 - 08:48 AM

Electrolytic caps have their lifetime depending on how long they worked and whether they were used in hard conditions (close to max voltage or filtering in switch mode PS) or not. Power supply ones would cause loud hum, bypasses would not pass the signal - simple as this.  

Most of our boomboxes used premium OEM capacitors which simply do not fail by themselves.

Buying cheap ones made in China does not make sense, premium ones by Matsushiata from let's say Digikey would cost an arm and a leg.

In reality only about 10-20% of caps must be replaced.   

Full recapping is surely a piece of mind but it's not worth it...



#13 superlew

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Posted 08 March 2015 - 09:47 AM

Most of our boomboxes used premium OEM capacitors which simply do not fail by themselves.

 

Funny, because I find failed/out-of-spec electrolytic caps in blasters all the time. It's not necessarily all of them, but still, quite a few.

I guess I'm picking up the wrong radios... :dunce:

 

As for re-capping the C-100 - Go for it!

Like Norm said, re-capping the electrolytics in the tuner board probably won't help with reception, but it won't hurt either.

My C-100 tends to get noisy in the tuner section about once a year. It seems to be a grounding issue with the tuning capacitor, which I clean with a little zero-residue tuner cleaner (DO NOT USE DEOXIT FOR THIS). Once clean, the reception is excellent.

I'm not saying this is the issue with yours, but I figured I'd throw it out there.

 

I'm sure someone will crucify me for cleaning the tuning cap, but it works in my case.



#14 toshik

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Posted 08 March 2015 - 10:22 AM

Upon receiving one, I'd clean it up, spray pots and switches, replace the belts and let it run for a few days. So whatever is faulty or leaky would fail.



#15 caution

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Posted 08 March 2015 - 11:22 AM

And that's probably a sensible thing to do in most cases. I'm doing them all because it's a wide open box and the boards are very accessible. A bunch of connectors, a few screws and you're prime time. It's also a classic box that deserves some extra TLC and would give me more peace of mind.  There is noticeable corrosion on a few areas so I am suspicious about the environmental conditions it was exposed to over its 31-year life. I'm also suspicious of the way it was used. It was already in the shop at least once for a blown HA1392, now an NTE ECG1606.



#16 Cpl-Chronic

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Posted 08 March 2015 - 12:24 PM

What about solid body caps like you see on computer boards now?  I hear they last a lot longer than standard pop-can electrolytics & are supposed to be very good too...

 

Cpl



#17 toshik

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Posted 08 March 2015 - 01:37 PM

What about solid body caps like you see on computer boards now?  I hear they last a lot longer than standard pop-can electrolytics & are supposed to be very good too...

 

Cpl

Ceramic ones would last forever unless they'd crack :-) Recent computer PCBs still use tiny electrolytic cans.



#18 blu_fuz

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Posted 09 March 2015 - 07:23 AM

 

Buying cheap ones made in China does not make sense, premium ones by Matsushiata from let's say Digikey would cost an arm and a leg.

 

 

I guess the definition of 'costing an arm and a leg' is determined by the user..... I bought and replaced about 135 caps in one boombox. All premium and maybe cost $40. I think that's a cheap way to protect your investment and they aren't that hard to replace.

 

 

By the time you take the time to pick caps to check, test, pull, and replace and you end up only changing 20% of them, it would take the same amount of time to replace them all and you can then remove those as a variable if you do any more testing.

 

If one of my boxes is suspected to need a cap, the others aren't going to be too far behind so I will replace them all on any amp circuit.



#19 toshik

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Posted 09 March 2015 - 07:58 AM

Also you should take into consideration risk of conductive lines separation from PCB while resoldering.



#20 blu_fuz

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Posted 09 March 2015 - 08:07 AM

I've had that happen more than once :-D. Having a variable temp solder iron and a proper solder sucker should help prevent this.