GA Pre 73 mod help

[Downthehatch]

Hello, I know this is a shot in the dark and my first post of any kind on this forum but I'm need of some help. I performed the Transformer mod on my Pre73 a while back and they worked out just fine however, I recently tried my hand at the the tantalum capacitor and output transistor mod. I may have jumped the gun on attempting these mods because I seemed to have fried a resistor. I fried the same resistor on a pair of pre73's so whatever went wrong has to do with the capacitors or output transformer. I opened a friends Pre73 that has the factory Zen Pro Mod and everything appears to be in check although there is a couple variances. I used 22uf50v instead of 22uf16v capacitors. However, I read that the higher voltage would no be an issue. I have also replaced the 1C1 and 2C1 capacitors with 22uf50v Tantalums. The Zen pro mod does not have these replaced but I don't see why they would cause anything to fry. The Zen Pro mod also replaced the 4c1 and 1c3 which are 10uf63v. I did not replace these. Still... doesn't make sense that those discrepancies would cause something to fry.  I also replaced the output transistor but mistakingly did not bias it. Could that be a probable candidate for this type of error. I'll post a picture of my mod so you can see where the resistor fried and if it means anything. Appreciate any advice on the subject. Cheers!

 

[Downthehatch]

I apologize for the extremely large image.

 

[Winetree]

I can't see them, but those big round Tantalums sometimes have a + and -.
Did you place them the right way?

 

[moamps]

..... I fried the same resistor on a pair of pre73's so whatever went wrong has to do with the capacitors or output transformer. .

The resistor is burned because the DC current thru the output transistor is too high. If you replaced the output transistor with another one, you must readjust its DC bias using (most probably) the blue trimmer resistor.

 

[Tekay]

Make sure you wired the output transformer correctly. You should have less than 1.0V over the 12R when correctly biased if the output transformer is loaded with 600 ohm.