Old BF194/195 Lockfit Transistors - TO-92 Si Equivalents

[sarakisof]

Hello everyone, i own some old Philicorda transistorised organs that use BF194 and BF195 transistors in oscillation cards / divider circuits.
Now as you may know those are the old type Si Lockfit package transistors that are prone to common failure and appear problems by aging. Just google "Lockfit transistors problems" or similar and you can see what I'm talking about.

I know that almost any common NPN TO92 Si (BC550, 337/8) will and can do the job fine, but i would like to find an equivalent as close as possible to the originals.
So far, i use BF494/495's. Are those the closest option to BF194/195's? What about BF241 , BF255?
I even found some NOS BF194/5s for cheap but I'm afraid to use them as exact same replacement, feels like asking for trouble again in the future.


http://www.peel.dk/Philips/Philicorda_GM-751.html

[antonis]

but i would like to find an equivalent as close as possible to the originals.

Is there any particular reason for that, Σοφοκλή..??

[iainpunk]

I don't think the transistors in these circuits have much impact on the sound, tbh.

I have a few jfets in that package, at least, i assume them to be jfets due to them having come in my possession in a bag labeled "N channel JFETs", and I haven't checked numbers yet.

Cheers

[sarakisof]

Snake oil - mojo rules - wife asked for   
Seriously, as i said above, practically any common NPN did the job fine indeed, but , just for the record, I'd like to know the closest to original ones option, schematic accordingly.
In what cases / circuits would be critical to use the same exact BF194/5s?

[iainpunk]

In what cases / circuits would be critical to use the same exact BF194/5s?

If there's a specific reason like its specific sound, noise profile or breakdown voltage when used as a negistor, but most probably its never a vital part.

Cheers

[sarakisof]

I see. For BF195 replacement, any preference between BF495 vs BF241 vs BF255?

https://www.web-bcs.com/transistor/tc/bf/BF195_sim.php

[PRR]

I don't think the transistors in these circuits have much impact on the sound, tbh.....

But a lot of them, so a major impact on the price. In those days.

And if they were dredging the reject barrels for barely useful parts, that may explain long-term crap-out.

It's digital dividers. Use any good part with suitable gender.

[sarakisof]

I don't think the transistors in these circuits have much impact on the sound, tbh.....

It's digital dividers. Use any good part with suitable gender.

I'm planning to replace all the BF195s (about 100pcs) in all dividers one day, so to avoid opening the thing every three months or so.
And, apart from death, sometimes Lockfits do fail really sneaky by producing a slight low freq "hiss like" sweet noise.

I can easily find plenty of BF495, BF251, BF255 's for 5-10 cents each in my area. Any pros one from another for straightforward replacing BF195s?

https://www.web-bcs.com/transistor/tc/bf/BF195_sim.php

[antonis]

BF241 or BF255 for BF195
(and BF240 or BF255 for BF194..)

edit: Sorry for using Greek here.. Confused while answering to P.M.

[sarakisof]

Tsipouro cheers