Crunch BMX1000 amp, some parts missing

[Pioneer621]

Hello everybody!

I got a Crunch BMX1000 two channel class AB amplifier a week or two ago, & although it looks like an easy one to work on, there is a part that looks to be missing I am not sure of. I will include pics so you can see what I am referring too.

It looks like a location to a capacitor but I am not certain; it is in parallel with a 1K ohm resistor, one side connects to the SECONDARY center tap of the power transformer, & the other side connects to the battery GROUND section of the board.

The location shows a capacitor goes there by the looks of it (hard to tell though), although the board number is R550, the resistor that is directly in parallel with it is labeled C550, so I think it was a mistake on the silk screen? What ever was there though looks like it burned up pretty bad & even burned a trace as someone put a solder bridge a crossed it, I cleaned the board a little before this photo.

Also, any ideas on which output transistors this amp uses or some good subs, they were taken out by the previous owner for something else, but I am mainly inquiring about the part that goes in the R550 location.

Thank you for any help on these missing parts, I greatly appreciate it.

Here are the pictures:







Solder side view of missing part:

[Perry Babin]

If you have higher resolution photos, email them to me.

babin_perry@yahoo.com

[Pioneer621]

Ok Perry, I sent the email. Hopefully I attached the pictures alright. My email starts with pioneer621, so you know where there coming from.

Thank you for the help!

[Perry Babin]

I doubt that it was ever installed.

[Pioneer621]

Ok, that makes things a little easier then, I really appreciate it man!

I will include another picture here that will hopefully be a clickable link if all else. But it was before I did any cleaning to the board at that part location & it looked like a part burned up there, as is why I thought I would ask. It does not seem like the part is a big deal so I won’t worry about it. Again, I can’t thank you enough for you taking the time to help. I’ll probably get the insulators in & make some clamps for the transistors / rectifiers & see if the power supply runs.

If I run into any other problems I will post back!

I’m curious to see if this link will be clickable & go to a decent size picture, but here is the pic of the board there before I did any cleaning & why I figured I would ask:

http://s3.postimage.org/xgw8zp94w/CR...021_edited.jpg

[Perry Babin]

It does appear that something burned there but any voltage that would have burned a capacitor (likely rated for at least 50v) would have also burned the resistor.

Also, it's not common to have a capacitor coupling the primary and secondary grounds. The 1k resistor is very common but not the cap.

[Pioneer621]

Yeah, the 1K resistor tests fine, so I don’t know if anything was ever in the other spot, but I do see what you’re saying since it seems fine.

I’m still learning on this stuff & when I see something I am not sure about I figure it’s a good idea to ask someone that does know. I’ve been trying to grasp how the amps work & the parts function in the circuit, etc. but it seems to be a slow process for me, but I still enjoy working on them, & I really do appreciate all the help.