Mark IV PSA

[Beyond Black]

I talked to Mike B at Mesa yesterday about sending my Triple in for some work, and talked to him for awhile about anything and everything. What a super cool dude. Anyway, he told me to check to see if my Mark IV has the big brown, Sprague 10,000, 16V caps. He said if it does, send it in immediately. Apparently when they go bad they emit a residue that gets all over the board, and takes him all day to clean, at about $600 to $800. So if you have a Mark IV, check it out. He asked for my serial number, and said it may have them. Mine is a B. I don’t know exactly which ones may have them.

 

[johnpace2]

Thanks is yours an A or B version?

 

[JimAnsell]

I talked to Mike B at Mesa yesterday about sending my Triple in for some work, and talked to him for awhile about anything and everything. What a super cool dude. Anyway, he told me to check to see if my Mark IV has the big brown, Sprague 10,000, 16V caps. He said if it does, send it in immediately. Apparently when they go bad they emit a residue that gets all over the board, and takes him all day to clean, at about $600 to $800. So if you have a Mark IV, check it out. He asked for my serial number, and said it may have them. Mine is a B. I don’t know exactly which ones may have them.

Good lookin out, my guy! gunna bust mine open today and check it out. He may have already had my amp in there, since i bought it used from mesa hollywood. it had the heatsink added on one of the op chips (where heat is problematic in early mark IV's), so i figured it had a once over already from someone at boogie.

mike b is the best btw. So patient and willing to let u pick his brain, even though he has to be a busy man, given his reputation.

 

[blackba]

Cool I will check to see if my has them. Mine is a 1990 mark IVA and is on the list to get some new caps at some point. Not looking forward to recapping this one as its going to be a pain.
I need to check the LDRs too.

 

[Beyond Black]

Mine is a B and the serial number is IV-011753. Like I said, I don’t know the span of the suspect amps, but I’d check them regardless. He actually said that if your amp has these, to stop playing it immediately and send it in.

 

[Beyond Black]

I talked to Mike B at Mesa yesterday about sending my Triple in for some work, and talked to him for awhile about anything and everything. What a super cool dude. Anyway, he told me to check to see if my Mark IV has the big brown, Sprague 10,000, 16V caps. He said if it does, send it in immediately. Apparently when they go bad they emit a residue that gets all over the board, and takes him all day to clean, at about $600 to $800. So if you have a Mark IV, check it out. He asked for my serial number, and said it may have them. Mine is a B. I don’t know exactly which ones may have them.

Good lookin out, my guy! gunna bust mine open today and check it out. He may have already had my amp in there, since i bought it used from mesa hollywood. it had the heatsink added on one of the op chips (where heat is problematic in early mark IV's), so i figured it had a once over already from someone at boogie.

mike b is the best btw. So patient and willing to let u pick his brain, even though he has to be a busy man, given his reputation.

My pleasure, bro. Hopefully this info is helpful to somebody. And yes, Mike B is incredibly cool to talk to! We probably talked about my amp for 5 minutes and all kinds of other shit for another 15. Laughing it up like I’ve known him for years! Great guy!

 

[psychodave]

It’s the A version (as I was told). And for what it’s worth the Mark IV I just sold was not one of them. I know because I too spoke with Mike B since I was going to send it in for a full service before selling it instead.

 

[Beyond Black]

It’s the A version (as I was told). And for what it’s worth the Mark IV I just sold was not one of them. I know because I too spoke with Mike B since I was going to send it in for a full service before selling it instead.

Cool, hopefully mine is cool then. I told him my serial number and that mine was a B, he said check it anyway.

 

[stephen sawall]

I haven't open mine in 18 years.

 

[JMMP]

Thanks for the PSA!
I just opened mine, no sign of any brown caps.
S/N 998X

 

[Beyond Black]

Thanks for the PSA!
I just opened mine, no sign of any brown caps.
S/N 998X

You’re welcome and good to hear.

 

[blackba]

Found the 3 dreaded brown caps in my mesa Mark IVA. They are 8200uF 16V in the version A. For the Version B they are 10,000uF 16V caps.

I went with 25V 8200uF caps just to give them a touch more margin as they are on a 12VAC tap before the bridge rectifier. Not looking forward to pulling the board, but it will be good learning as I haven't done much to this amp.

Going to check the vactrols while I am in there. Also considering replacing the master volume pot to see if I can get one that is less touchy. Its a 250k Audio taper switched, mine measures 217kohms.

 

[Beyond Black]

Found the 3 dreaded brown caps in my mesa Mark IVA. They are 8200uF 16V in the version A. For the Version B they are 10,000uF 16V caps.

I went with 25V 8200uF caps just to give them a touch more margin as they are on a 12VAC tap before the bridge rectifier. Not looking forward to pulling the board, but it will be good learning as I haven't done much to this amp.

Going to check the vactrols while I am in there. Also considering replacing the master volume pot to see if I can get one that is less touchy. Its a 250k Audio taper switched, mine measures 217kohms.

That sucks, man. Is changing these caps a difficult job? Is it something any decent amp tech could do?

 

[blackba]

Found the 3 dreaded brown caps in my mesa Mark IVA. They are 8200uF 16V in the version A. For the Version B they are 10,000uF 16V caps.

I went with 25V 8200uF caps just to give them a touch more margin as they are on a 12VAC tap before the bridge rectifier. Not looking forward to pulling the board, but it will be good learning as I haven't done much to this amp.

Going to check the vactrols while I am in there. Also considering replacing the master volume pot to see if I can get one that is less touchy. Its a 250k Audio taper switched, mine measures 217kohms.

That sucks, man. Is changing these caps a difficult job? Is it something any decent amp tech could do?

They are radial caps, so you have to pull the whole main board to get to them, which looks to me like all the pots will need to be removed from the front panel and then you can flip up the board. So looking labor intensive to me, but I am wanting to do this myself so I learn the amp more.

I will report back once I get the update done, may be a while as my amps get last priority. I did get all the parts on order.

 

[acalaf]

I just looked inside my mark iva. are these the caps in question? thanks

 

[blackba]

I just looked inside my mark iva. are these the caps in question? thanks

Yes, those are the ones. 8200uF, 16V for the mark IVA like you have. You can see if they explode that they would create a huge mess to clean up.


Here are the ones I bought to replace them. https://www.mouser.com/ProductDetail/66 ... 0E822MMP1S
I got 25V caps, but 16V like the originals will be fine, I just wanted a little more head room.

It would be cool to know what Mesa is charging for a recap of a mark IV if anyone has that info.

 

[acalaf]

thanks. Not sure how much mesa charges but it looks like you can do it yourself. I did my power and filter caps and the amps sounds great, super punchy.

 

[Beyond Black]

Mike B told me $200 for a full recap of my Rev G Triple Rec.

 

[blackba]

thanks. Not sure how much mesa charges but it looks like you can do it yourself. I did my power and filter caps and the amps sounds great, super punchy.

Cool, didn't notice the replaced 30uF 500V caps when I first looked at the picture. Any tips on pulling the board? Do you have to pull off all the pots? Are you planning to replace the 8200uF brown caps yourself?

 

[stephen sawall]

My capacitors are 30 years old. They need to be replaced anyway.
My Mark IV, Tremoverb and Heartbreaker all need it done.