AU-X1

[Willy6]

You will be very lucky to find 'new ones' anywhere, as the OP transistors haven't been made for decades. When I removed mine I checked they were OK but kept the transistors from each channel separate, and noted their positions.

If you find that you can't make a complete set, or you can make one set but not two, then you should (on one amp) change them all for T03P substitutes, like the guy with the AU-X11 did so well in his thread.

How low on current gain would you let one get before you decided to put substitutes in?

 

[Hyperion]

How low on current gain would you let one get before you decided to put substitutes in?

Good question - I don't know the answer to that.

I should think it depends how close to the others, and particularly its NPN or PNP opposite number it is. In other words being all low, say '20' isn't as much of a problem as if you had one or more low and the others at say 60 for example. The numbers you have posted are acceptable if I am any judge, and remember that power transistor hFE as measured on an 'ordinary low current tester' at least, are never very high.

 

[Willy6]

Good question - I don't know the answer to that.

I should think it depends how close to the others, and particularly its NPN or PNP opposite number it is. In other words being all low, say '20' isn't as much of a problem as if you had one or more low and the others at say 60 for example. The numbers you have posted are acceptable if I am any judge, and remember that power transistor hFE as measured on an 'ordinary low current tester' at least,re never very high.

I have 24 to choose from (as long as they're all still good anyway) and i'll try to match them up as close as possible.

 

[Willy6]

I have 24 to choose from (as long as they're all still good anyway) and i'll try to match them up as close as possible.

I measured them with this tester..

 

[JOMARK911]

I agree with John.Just keep them as close as you can and you'll be ok.

 

[Willy6]

My second mouser order came today and I bought as much of the nichicon fg series I could find but one that I needed was on back order so I got a panasonic ECA-1cm102 that they recommended for audio/video I guess they are new to mouser and they have low esr,high ripple current and long life.Anyone want to chime in on these before I install them?

 

[Hyperion]

What circuit position?

F-???? & C?? (14 locations, I used 16V in place of 10V to simplify parts order - all better)

Edit update
I have just checked the value and voltage (obvious where they go) - yes they will be better than the FG's for this purpose.

 

[Willy6]

What circuit position?

F-???? & C?? (14 locations - all better)

Edit update
I have just checked the value and voltage (obvious where they go) - yes they will be better than the FG's for this purpose.

Ya the 16v 1000uf on f-2917 but I did get the fg for the 10v 1000uf ones.By the way I read that the glue that they used to hold them down is conductive what's the best way to remove old glue on these boards?

 

[Hyperion]

what's the best way to remove old glue on these boards?

Something Toluene based - I use Hammerite Thinners - works well, it needs to be scraped off with something sharp made of tough plastic, I used (on Ron's suggestion) a sharpened chopstick (LOL) it worked a treat. If you use a screwdriver you'll lose all the board markings

Just remember to leave the Toluene based cleaner on there for at least 5 minutes to allow it to do its merry work.

Search AK for 'Sansui Glue' if you want names of alternative chemicals for softening it.

 

[Willy6]

Something Toluene based - I use Hammerite Thinners - works well, it needs to be scraped off with something sharp made of tough plastic, I used (on Ron's suggestion) a sharpened chopstick (LOL) it worked a treat. If you use a screwdriver you'll lose all the board markings

Just remember to leave the Toluene based cleaner on there for at least 5 minutes to allow it to do its merry work.

Search AK for 'Sansui Glue' if you want alternative chemicals for softening it

I bought 20 of those 16v panasonic's if I have enough I'll probably use all those instead of the 10v fg's

 

[Hyperion]

Yep, good idea.

 

[Leestereo]

Ethyl acetate or acetone will also soften the old glue for easier removal; and will not damage the board silk screening. As these solvents are the active ingredients in nail polish remover, they are readily sourced.

 

[Willy6]

Ethyl acetate or acetone will also soften the old glue for easier removal; and will not damage the board silk screening. As these solvents are the active ingredients in nail polish remover, they are readily sourced.

I guess I'll consult with my wife

 

[Leestereo]

I bought 20 of those 16v panasonic's if I have enough I'll probably use all those instead of the 10v fg's

Whenever possible, it is best to avoid using electrolytic capacitors with low voltage ratings as these are more susceptible to "drying out"/failure and they don't perform as well as their higher voltage brethren. AK member ConradH has documented his findings on low voltage capacitors here: http://conradhoffman.com/capchecktut.htm; a very worthwhile read.

 

[Willy6]

Whenever possible, it is best to avoid using electrolytic capacitors with low voltage ratings as these are more susceptible to "drying out"/failure and they don't perform as well as their higher voltage brethren. AK member ConradH has documented his findings on low voltage capacitors here: http://conradhoffman.com/capchecktut.htm; a very worthwhile read.

I'm very thankful for you guys putting up with all my questions and I'm learning more and more every day from all the positive input...

 

[Ronito6]

The glue is easily conquered with lacquer thinner.

As Harolda pointed out, chopsticks work great to scrape away the softened glue after the lacquer thinner has done its work.

A sharpened chopstick (or I suppose a wooden ice cream spoon or a Popsicle / ice-lolly stick ) will have enough strength to withstand the leverage needed to scrape the glue, BUT will be soft enough to leave the silkscreen printing on your PC board completely unharmed. Also the wood's roughness catches the glue very well. In the end, with minimal effort, only the glue will be removed and your board will look factory fresh.

Not only is it a cheap tool but disposable to boot, so cleanup is easier too.

BTW: Nail polish remover may have buffering chemicals and in my experience does not work as well as lacquer thinner.

Lacquer thinner works better as it is mostly toluene.

 

[Hyperion]

Whenever possible, it is best to avoid using electrolytic capacitors with low voltage ratings as these are more susceptible to "drying out"/failure and they don't perform as well as their higher voltage brethren. AK member ConradH has documented his findings on low voltage capacitors here: http://conradhoffman.com/capchecktut.htm; a very worthwhile read.

+1 I follow Conrad's advice too, I avoid buying any electrolytic rated below 16V if I can possibly help it, hence the mix of 10V and 16V 1000µF capacitors for my AU-X1 all became 16V for the above reason, and also to simplify ordering, (and eventual fitting), of these parts.

 

[Ronito6]

+1 I follow Conrad's advice too, I avoid buying any electrolytic rated below 16V if I can possibly help it, hence the mix of 10V and 16V 1000µF capacitors for my AU-X1 all became 16V for the above reason, and also to simplify ordering, (and eventual fitting), of these parts.

Just to add a couple cents here: According to a pm chat I had with Oilmaster a while ago he said that going a step up in voltage with a new cap was fine and even preferable. Going too high would however mess up the quality of a circuit as capacitors require "a certain tension" to function properly / efficiently.

That said...would replacing the lower voltage electrolytic caps with polypropylene film caps be OK?

 

[Willy6]

Just to add a couple cents here: According to a pm chat I had with Oilmaster a while ago he said that going a step up in voltage with a new cap was fine and even preferable. Going too high would however mess up the quality of a circuit as capacitors require "a certain tension" to function properly / efficiently.

That said...would replacing the lower voltage electrolytic caps with polypropylene film caps be OK?

So if the old cap was 10v and a step up is fine and even preferable to say 16v is 25v or even 50v to high?

 

[Willy6]

So if the old cap was 10v and a step up is fine and even preferable to say 16v is 25v or even 50v to high?

There has been a few cases where I could not find one in the right voltage and stepped it up quite a bit.