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PostPosted: Tue Apr 25, 2017 8:43 pm 
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The Nostalgia Co wrote:
Output transistors can be checked for leakage and if they test fine, then there is no need to replace them.

As far as electrolytic capacitors, they do in fact have rated lifespan based on hours and operating temperature. They also have a shelf life rating. The ratings are contained in the data sheet for the cap.
There are two main reasons to re-cap a unit.

1) Preventative maintenance. There are parts in vintage units that are no longer available. Capacitors that are operating well past their lifespan risk damaging parts that are no longer available if they fail.
2) Sound quality. Old electrolytic can leak physically and electrically. They also increase in resistance. The combined effect can roll off high frequencies. What some people call the “warm vintage sound” can actually be caused by out of spec electrolytics. The unit can sound slow, too warm and muddy. Recapping can improve high frequency response. Is the unit actually working as designed when operating with functional but out of spec capacitors??

I have had the discussion regarding “if it aint broke don’t fix it” discussion with older technicians as well and I disagree. When these old guys were servicing the Pioneers, Marantzs, Sansui etc they weren’t vintage and parts were readily available. I would hate to see a Pioneer SX-1080 turn into a boat anchor because of no preventive maintenance. There are no replacement output transistors for that unit.

In my opinion, many of the old techs don’t want to re-cap because it is time consuming and hard to make a decent buck from it. I read one well known tech in the USA explain that at the end of the day when he calculates the amount of time into a unit per hour, he basically makes minimum wage. Additionally to check the health of a capacitor; you need to take it out of circuit. Again, very time consuming and little $ per hour. Some people don’t like to pay for the labour in a disposable society.

I provide my customers with options and let them make the decision. If they only want a repair then that is what I do. If re-capping doesn’t add value to a unit then I tell them. If a unit is nostalgic to them and they want it recapped I can do that. If they want it restored I can provide that service as well. For a piece that has value but money is tight, I usually recommend recapping the heat accumulation and protection areas. That means the power supply, amplifier, and protection circuitry. This can be either the protection circuit (DC coupled unit) or the output capacitors (in a cap coupled unit).


thats a reasonable explanation as for the capacitors replacing..one tech over the phone told me those capacitors made back then were made and sealed very well and have a long lifespan...much better than the ones made in china of today
. Do you have the tools to do tuner alignments as well?


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PostPosted: Tue Apr 25, 2017 9:04 pm 
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FRAUDBUSTER wrote:
The Nostalgia Co wrote:
Output transistors can be checked for leakage and if they test fine, then there is no need to replace them.

As far as electrolytic capacitors, they do in fact have rated lifespan based on hours and operating temperature. They also have a shelf life rating. The ratings are contained in the data sheet for the cap.
There are two main reasons to re-cap a unit.

1) Preventative maintenance. There are parts in vintage units that are no longer available. Capacitors that are operating well past their lifespan risk damaging parts that are no longer available if they fail.
2) Sound quality. Old electrolytic can leak physically and electrically. They also increase in resistance. The combined effect can roll off high frequencies. What some people call the “warm vintage sound” can actually be caused by out of spec electrolytics. The unit can sound slow, too warm and muddy. Recapping can improve high frequency response. Is the unit actually working as designed when operating with functional but out of spec capacitors??

I have had the discussion regarding “if it aint broke don’t fix it” discussion with older technicians as well and I disagree. When these old guys were servicing the Pioneers, Marantzs, Sansui etc they weren’t vintage and parts were readily available. I would hate to see a Pioneer SX-1080 turn into a boat anchor because of no preventive maintenance. There are no replacement output transistors for that unit.

In my opinion, many of the old techs don’t want to re-cap because it is time consuming and hard to make a decent buck from it. I read one well known tech in the USA explain that at the end of the day when he calculates the amount of time into a unit per hour, he basically makes minimum wage. Additionally to check the health of a capacitor; you need to take it out of circuit. Again, very time consuming and little $ per hour. Some people don’t like to pay for the labour in a disposable society.

I provide my customers with options and let them make the decision. If they only want a repair then that is what I do. If re-capping doesn’t add value to a unit then I tell them. If a unit is nostalgic to them and they want it recapped I can do that. If they want it restored I can provide that service as well. For a piece that has value but money is tight, I usually recommend recapping the heat accumulation and protection areas. That means the power supply, amplifier, and protection circuitry. This can be either the protection circuit (DC coupled unit) or the output capacitors (in a cap coupled unit).


thats a reasonable explanation as for the capacitors replacing..one tech over the phone told me those capacitors made back then were made and sealed very well and have a long lifespan...much better than the ones made in china of today
. Do you have the tools to do tuner alignments as well?

+1 for the explanation, and
+1 for the alignment question.
Thx

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PostPosted: Wed Apr 26, 2017 2:47 am 
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The Nostalgia Co wrote:
Output transistors can be checked for leakage and if they test fine, then there is no need to replace them.

As far as electrolytic capacitors, they do in fact have rated lifespan based on hours and operating temperature. They also have a shelf life rating. The ratings are contained in the data sheet for the cap.
There are two main reasons to re-cap a unit.

1) Preventative maintenance. There are parts in vintage units that are no longer available. Capacitors that are operating well past their lifespan risk damaging parts that are no longer available if they fail.
2) Sound quality. Old electrolytic can leak physically and electrically. They also increase in resistance. The combined effect can roll off high frequencies. What some people call the “warm vintage sound” can actually be caused by out of spec electrolytics. The unit can sound slow, too warm and muddy. Recapping can improve high frequency response. Is the unit actually working as designed when operating with functional but out of spec capacitors??

I have had the discussion regarding “if it aint broke don’t fix it” discussion with older technicians as well and I disagree. When these old guys were servicing the Pioneers, Marantzs, Sansui etc they weren’t vintage and parts were readily available. I would hate to see a Pioneer SX-1080 turn into a boat anchor because of no preventive maintenance. There are no replacement output transistors for that unit.

...



+ + + There's a reason Bryston has a 20 year warranty. If you don't do PM on 20+ year old gear you'll just be sinking even more $$ into the piece over time. Or it'll just crap out and possibly be unrepairable. Some gear is worth the investment and some isn't.

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Collecting vintage tube Pilot (Pilotone) HiFi gear.


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PostPosted: Wed Apr 26, 2017 6:32 am 
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Replacing the capacitor is an 'accumulation of odds'..that drift into the inevitable. It's Russian roulette, with no need for a final electronic bang at the end. So recap old gear. No if, ands, buts or maybes. Anything else is just wishful thinking. Or the given person facing the costs is listening to the wrong advice, as that advice is emotionally expedient and agreeable. :)

Transistors do leak, but it is not all that common. Most transistors will have an near indeterminate lifespan. For most of this older gear, the problem areas are already known and shared, via the Internet's record on forums or whatnot.

Newer capacitors are at least as well made as the old, but it is largely dependent on buying them from the same companies that were making them back then, 20-40+ years ago.

Some of the newer gear that appeared to be cheaper, back in the 80's and onward, many to most times they sourced their capacitors from places that did not have the lore and the experience over time, to make good capacitors.

Researching about the given item in question - is key.

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PostPosted: Wed Apr 26, 2017 6:59 am 
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Output transistors don't leak. If anything the heat paste between the OT and heat sink dries up and a refresh is good. The usual culprit is always the power supply boards for caps which definitely affect the rest of unit. For caps being changed, sure play around where say the signal path goes through. You can do "upgrades" like for example a 700C Kenwood. Good threads on them. The simplest example of a cap making a huge difference is in an A25 Dynaco. Changing that single passive cap is a HUGE difference when you left right them after.


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PostPosted: Wed Apr 26, 2017 9:22 am 
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byefi wrote:
Output transistors don't leak. If anything the heat paste between the OT and heat sink dries up and a refresh is good. The usual culprit is always the power supply boards for caps which definitely affect the rest of unit. For caps being changed, sure play around where say the signal path goes through. You can do "upgrades" like for example a 700C Kenwood. Good threads on them. The simplest example of a cap making a huge difference is in an A25 Dynaco. Changing that single passive cap is a HUGE difference when you left right them after.


They can leak electrically but it is not too common. When you are replacing the thermal paste it is good practice to test for leakage current.


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PostPosted: Wed Apr 26, 2017 9:36 am 
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You should not replace transistors with modern/better ones, as the circuit can become unstable with faster/better parts. Replacement then requires that the circuit is redesigned and/or values of supporting parts are changed. Not recommended.


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PostPosted: Wed Apr 26, 2017 9:48 am 
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Bumpy wrote:
You should not replace transistors with modern/better ones, as the circuit can become unstable with faster/better parts. Replacement then requires that the circuit is redesigned and/or values of supporting parts are changed. Not recommended.


As a blanket statement I disagree. Yes you can have issues if you don't use replacements with similar ratings. A components data sheet provides more than enough technical information.

I replace transistors every day that test fine. With the age of these units certain parts have revealed themselves as problematic. In Pioneer units the 2sa725 and 726 come to mind. They are known noise generators. They can test fine but still cause an elevated noise floor, hissing, and popping.


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PostPosted: Wed Apr 26, 2017 10:02 am 
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Good idea to replace all the electrolytics in 40 year old equipment with new Japanese branded electrolytics ( 105 C caps preferred). Panasonic, Nichicon, Elna, United cemcon. Stay away from cheap Chinese capacitors like Jamicon etc. Because if the old caps arent bad this week, they will be next week. It's long past the lifetime of the originals and the new ones will give the unit another 20 to 40 years of life. The cost of good caps is cheap compared to the service labour.


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PostPosted: Wed Apr 26, 2017 10:04 am 
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FRAUDBUSTER wrote:
[

thats a reasonable explanation as for the capacitors replacing..one tech over the phone told me those capacitors made back then were made and sealed very well and have a long lifespan...much better than the ones made in china of today
. Do you have the tools to do tuner alignments as well?


In my opinion today's electrolytics are better made provided you use the top manufacturers. I tend to use Panasonic, Nichicon and Elna. These companies are the same companies that provided the original caps, along with some others. Vintage gear has caps that are rated for an 85 degrees Celsius upper operating temparature. In power supplies rebuilds I like to use either Panasonic FC or Nichicon PW. Both are rated for a 105 degrees upper limit which prolongs lifespan. With modern technologies new electrolytics are smaller in size. This allows you to increase the voltage rating of the capacitor when replacing. In areas that operate close to an older caps voltage rating, the increase in rating can help prolong lifespan as well.

Regarding the tuner alignment. I recently purchased the gear but haven't been able to find the time to go through the operating manual. I have some thrift store tunes to work on, and when I feel comfortable offering the service I will post in the dealer forum.


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PostPosted: Wed Apr 26, 2017 10:27 am 
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I just picked up a mid 80's Sugden P28 power amp. SS, Class A/B.

Having a local tech (Dan Santoni) go through it. The amp works, but I want to hang on to it for a long time, so spending some $ to have it reviewed and likely replace the capacitors feels right to me.

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PostPosted: Wed Apr 26, 2017 12:05 pm 
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The Nostalgia Co wrote:
Bumpy wrote:
You should not replace transistors with modern/better ones, as the circuit can become unstable with faster/better parts. Replacement then requires that the circuit is redesigned and/or values of supporting parts are changed. Not recommended.


As a blanket statement I disagree. Yes you can have issues if you don't use replacements with similar ratings. A components data sheet provides more than enough technical information.

I replace transistors every day that test fine. With the age of these units certain parts have revealed themselves as problematic. In Pioneer units the 2sa725 and 726 come to mind. They are known noise generators. They can test fine but still cause an elevated noise floor, hissing, and popping.


Certainly, you can replace transistors whose characteristics match. As you point out, that can be a good thing....

My comment is a general warning. There are devices that cannot have components upgraded so easily. eg. Phase linear 400 driver transistors cannot be updated to faster ones without causing destructive oscillation.

The general thinking is that if modern is better, so must be modern transistors. That is not always so easily done.

Some care need be taken.


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PostPosted: Sat May 20, 2017 8:26 am 
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FRAUDBUSTER wrote:
and all capacitors replaced? What ever happened to "if it aint broke dont fix it"? And where is the expiry dates on the output transistors and capacitors? Im sorry but its a cash grab total replacing critical original output transistors in lets say a marantz sansui pioneer etc unless they are blown. Before when took things for repair they fixed just the bad trans capacitor and resistor now when you take it in to everyone they want to overhaul the whole thing. Its really unneccessary.

Capacitors have come a long way since vintage gear was built and since caps cost pennies they might as well be replaced. It would be foolish to leave them in. Forty year old caps would be passed their prime to say the least and new ones sound a whole lot better. As long as the unit is in for repair anyways the additional cost would be minimal. If a vintage receiver is 100 % functional I would only replace caps when there is a malfunction and then yes to all of them. Repairs should always be based on the value of the vintage gear. If the unit is desirable enough to keep and a tech suggested to only replace the bad caps I'd find myself a new tech. Caps have their own sonic signature, and if they're in the signal path mixing new with old is not ideal.


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PostPosted: Sat May 20, 2017 9:40 am 
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oddio1 wrote:
FRAUDBUSTER wrote:
and all capacitors replaced? What ever happened to "if it aint broke dont fix it"? And where is the expiry dates on the output transistors and capacitors? Im sorry but its a cash grab total replacing critical original output transistors in lets say a marantz sansui pioneer etc unless they are blown. Before when took things for repair they fixed just the bad trans capacitor and resistor now when you take it in to everyone they want to overhaul the whole thing. Its really unneccessary.

Capacitors have come a long way since vintage gear was built and since caps cost pennies they might as well be replaced. It would be foolish to leave them in. Forty year old caps would be passed their prime to say the least and new ones sound a whole lot better. As long as the unit is in for repair anyways the additional cost would be minimal. If a vintage receiver is 100 % functional I would only replace caps when there is a malfunction and then yes to all of them. Repairs should always be based on the value of the vintage gear. If the unit is desirable enough to keep and a tech suggested to only replace the bad caps I'd find myself a new tech. Caps have their own sonic signature, and if they're in the signal path mixing new with old is not ideal.
+1


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PostPosted: Sat May 20, 2017 11:19 am 
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FRAUDBUSTER wrote:
and all capacitors replaced? What ever happened to "if it aint broke dont fix it"? And where is the expiry dates on the output transistors and capacitors? Im sorry but its a cash grab total replacing critical original output transistors in lets say a marantz sansui pioneer etc unless they are blown. Before when took things for repair they fixed just the bad trans capacitor and resistor now when you take it in to everyone they want to overhaul the whole thing. Its really unneccessary.

YES. And capacitor's and all other "leaky" (or age-dependent ) parts. If the item is worthy of such repair prices.
Current, quality Hi-Fi is far superior to the old stuff --regardless of the "legend" preceding it. There are a FEW gems, to be sure. All other Hi-Fi at such an (advanced) age should be replaced. And fast.


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