Mc240 w/ "Black Beauties" only

[DrRobocop]

Hi all,

I was planning on completely recapping my mc240 and noticed that all the capacitors appear to be the "black beauty" caps with no bumblebees. Is there any significance to this? Is this better/worse/no difference from the bumble bees?
From reading various threads, I have seen it recommended to retain the .22 black beauties and remove the surrounding bumblebees. Does this advice extend to the other black beauty caps? Should I test the values but err on the side of keeping them in place?

thanks!

 

[mcgjohn]

before you do anything, may want to see if any of hte caps are leaking DC.

If they are still good, would tend to leave them in place.

If you find a few leakers, then you have to address which cap you are going to replace them with. A large question since there are so many available, from standard to high end boutique grades....

 

[Pio1980]

If Sprague 160P, they are probably ok. Check for leakage by checking operating voltages at both ends.

 

[DrRobocop]

Thanks for the helpful replies!

They are all 160Ps. I'll test the caps and see what needs to be replaced. I assume those little yellow/translucent 100UF electrolytic caps in the front (far left in the pic) would likely need to go at this point regardless.
I wonder though, is this a normal configuration? I've just never seen an all black beauty mc240 depicted online, or in my limited experience looking under the hood of other mc240s I've come across.

Also, do you have any recommendations for good replacement caps? I've been thinking of using the Arizona Blue or Green Cactus caps which are much touted on Jeff's Place. Is there a general consensus on which caps tend to be preferred in old macs?

 

[pgena]

Mine in its original configuration. I left the row of Black Beauties, but replaced all other caps.

 

[Pio1980]

Thanks for the helpful replies!

They are all 160Ps. I'll test the caps and see what needs to be replaced. I assume those little yellow/translucent 100UF electrolytic caps in the front (far left in the pic) would likely need to go at this point regardless.
I wonder though, is this a normal configuration? I've just never seen an all black beauty mc240 depicted online, or in my limited experience looking under the hood of other mc240s I've come across.

Also, do you have any recommendations for good replacement caps? I've been thinking of using the Arizona Blue or Green Cactus caps which are much touted on Jeff's Place. Is there a general consensus on which caps tend to be preferred in old macs?

All 160P is kind of unusual in these, keep them if good. Replace all of the OEM elyticaps and all resistors out of spec.

 

[DrRobocop]

Thanks for your help Guys!

Yeah, I thought it was a bit odd but it looks like I'm not the only one out there with the black beauty version of the MC240. I'll run through the unit to see what is out of spec and replace as needed.

 

[SaturationPt]

Mine is a low-hour with all 160Ps also (black beauty). I tested and found no leakers, replaced the audio coupling caps next to the input switch with K40s, Authenticap replacements for the PS, new thermistor, all bias resistors tested excellent, and updated the selenium to a modern diode rectifier. All is great, I do love the amp.

You also likely have the later diodes in the outboard two slots like the photo above, earlier amps with the "bumblebees" have large diodes mounted in fuseholders to support them.

Does yours still have the voltage selector switch?