Twenty years have passed, what to do?

[Gionni]

First of all do a salute to the entire board. I am a happy owner of two finals SA/6e mono since 20 years have passed, wondering if the power transistors and capacitors are to be replaced or not. Thanks for the reply.

 

[Zen Mod]

transistor - why ?

caps - only ESR meter can tell

you have nice ones (uproc based) for peanuts on ebay


esr meter | eBay

 

[Gionni]

Hello Zen Mod I do not speak English, and with the automatic translator I do not understand very well. you're telling me that the transistors are not to be changed?

 

[Zen Mod]

there is no need to change transistors

check caps with ESR meter - cheap on ebay , look at previously posted link

google translate from Serbian to Italian :

non vi è alcuna necessità di sostituire i transistori

controllare i condensatori con ESR metro a buon mercato su ebay, vedi link precedentemente scritto

 

[flg]

Just so you know, transistors are subject to metal migration, amongst other reliability issues, where over time, temp and high current, metal atactually moves leaving the metal thin or missing in some spots. This is especially bad when the metal travels over steps on the die surface, where it was thin when freshly manufactured. This can cause catastrophic falure

 

[Gionni]

there is no need to change transistors

check caps with ESR meter - cheap on ebay , look at previously posted link

google translate from Serbian to Italian :

non vi è alcuna necessità di sostituire i transistori

controllare i condensatori con ESR metro a buon mercato su ebay, vedi link precedentemente scritto

Thanks Zen Mod'll measurement of capacitors with ESR meter.

 

[Gionni]

Just so you know, transistors are subject to metal migration, amongst other reliability issues, where over time, temp and high current, metal atactually moves leaving the metal thin or missing in some spots. This is especially bad when the metal travels over steps on the die surface, where it was thin when freshly manufactured. This can cause catastrophic falure

Hello FLG would you advise me to replace the transistor? you know the suppliers who sell the transistors marked Motorola?

 

[flg]

Hello FLG would you advise me to replace the transistor? you know the suppliers who sell the transistors marked Motorola?

I would imagine it is unlikely your 20 year old amp has seen as much use as that might suggest. I would not change them purely because of age.
As ZM says though, caps dry out and other things that happen even on the self. Measuring them is a good idea. Changing to a modern upgraded component might be an improvement in sound in addition to reliability/safety?
I know the typical USA suppliers? Transistors marked Motorola were made buy Motorola. That Business however was sold to ON Semiconductor in '98 maybe.

 

[Gionni]

I would imagine it is unlikely your 20 year old amp has seen as much use as that might suggest. I would not change them purely because of age.
As ZM says though, caps dry out and other things that happen even on the self. Measuring them is a good idea. Changing to a modern upgraded component might be an improvement in sound in addition to reliability/safety?
I know the typical USA suppliers? Transistors marked Motorola were made buy Motorola. That Business however was sold to ON Semiconductor in '98 maybe.

Thanks FLG advice

 

[Gionni]

I would imagine it is unlikely your 20 year old amp has seen as much use as that might suggest. I would not change them purely because of age.
As ZM says though, caps dry out and other things that happen even on the self. Measuring them is a good idea. Changing to a modern upgraded component might be an improvement in sound in addition to reliability/safety?
I know the typical USA suppliers? Transistors marked Motorola were made buy Motorola. That Business however was sold to ON Semiconductor in '98 maybe.

I was informed if these components are subject to wear because I read that Motorola transistors are no longer available, however you're telling me that the transistors are always produced by ON Semiconductor "very good" but I do not know when I will make a final restoration of to feel comfortable for another 20 years.
You do not know the mica list of components (transistors) that are in the finals SA/6e
Thank you all for the answers
Gionni.

 

[flg]

Transistors sitting on the shelf are not subject to "wear" or degradation that we should worry about. Possibly, lead oxidation would be the only concern. Buying actual Motorola transistors is still posible because of the large stock of some wharehouses and distributors, even though they were actually manufactured 15 years ago. There is however the possibility of fakes! As far as I know, and I worked at ON Semi at the time, all the part numbers that still existed were being manufactured with the same equipment to the same spec, and even in some cases by the same people, as the Motorola marked devices. They just took over the facilities and/or the equipment and continued production. Device numbers that are equivalent are being marketed and sold under the ON Semi name currently. Just as our popular IRF devices are now produced by Vishay, some of the Motorola devices may have been discontinued by them or ON Semi and sold to others to produce. The closest you can get to a real Motorola "New" part will be sold by ON Semi today.

 

[Gionni]

FLG thanks you've been very helpful, excellent explanation, I could not find more competent person / qualified.