Search found 206 matches

by jrb32
Wed Apr 01, 2020 11:45 am
Forum: Mark Series
Topic: Is an upgraded c+ a legit c+?
Replies: 9
Views: 696

Re: Is an upgraded c+ a legit c+?

Someone sent me a message on reverb.com about a listing I have for an upgraded c+ HRG. He's trying to tell me it's not a c+. I told him to ask Mike B. if it's a c+ since Mike's the one that puts the plus mark on the upgrades. What do you guys think? Yes. An upgraded C+ is a legit C+. All 'factory C...
by jrb32
Wed Apr 01, 2020 11:26 am
Forum: Vintage Amps (Before 1991)
Topic: Putting together a Mark III Guide
Replies: 37
Views: 6901

Re: Putting together a Mark III Guide

Haven't been on for a while, but quick shouts to all U guys for TRULY STUNNING work..!! Level of detail, sense of support for this amp but also M/B.. Big high 5's all round - of course maintaining social distance tho'..!!! Cheers, Dave No problem thanks Dave! I've put a new post up at the start tha...
by jrb32
Tue Nov 19, 2019 12:54 pm
Forum: Mark Series
Topic: The forgotten and unsupported pure MK II C
Replies: 15
Views: 1339

Re: The forgotten and unsupported pure MK II C

The IIC and the early IIC+s shipped out with the IIB schematic. Not sure why but that's just the way it was historically. I haven't compared the IIB and IIC from a circuit point of view but perhaps they are similar in certain ways? There could also be an element of stopping people copying the amp or...
by jrb32
Mon Nov 18, 2019 3:34 pm
Forum: Vintage Amps (Before 1991)
Topic: Mark III bass control question
Replies: 4
Views: 572

Re: Mark III bass control question

Can always hook up a multimeter in resistance mode to the pots with the amp off and check the difference in resistance as the knob is turned to check the pot is actually working properly within the limits it's meant to? If you can eliminate that as working correctly then maybe look around further. T...
by jrb32
Mon Nov 18, 2019 3:24 pm
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 12702

Re: Mark IIC (not IIC+) draft schematic

Thanks a lot I'll update that switching part on the schematic. Cheers :D
by jrb32
Thu Nov 14, 2019 4:43 pm
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 12702

Re: Mark IIC (not IIC+) draft schematic

Also if you still have that picture of the bottom of the IIC+ PCB you could upload in a similar way I could kiss you right now! :lol:
by jrb32
Thu Nov 14, 2019 4:41 pm
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 12702

Re: Mark IIC (not IIC+) draft schematic

Hi, that schematic contains the same error in the switching circuit that was present in the original Mesa schems. Here's the actual circuit: (I've traced more than one 2C, a 2C+ and also MKIVB) https://lh5.googleusercontent.com/iRIK9weqLC2OPEAIrD8mdKJ8BXh0-HdG6sWln6Y2f1iKkRq9LaO1qOba-cnF2cJzh7V2XKm...
by jrb32
Thu Nov 14, 2019 7:39 am
Forum: Mark Series
Topic: The forgotten and unsupported pure MK II C
Replies: 15
Views: 1339

Re: The forgotten and unsupported pure MK II C

Schematics for the MKII C + are available EVERYWHERE and all over the internet while schematics for the original MK II C can not be found. MBoogie made around 1400 of the pure MKII C before the transition to the C+. MBoogie totally disowned and removed all documentation support for the pure II C ca...
by jrb32
Thu Nov 14, 2019 7:37 am
Forum: Mark Series
Topic: Mark IIC (not IIC+) draft schematic
Replies: 26
Views: 12702

Re: Mark IIC (not IIC+) draft schematic

RP10 IIC Schematic: https://drive.google.com/open?id=1mpJFsu2gHA2gIiNmg6FGbC81rlggkt6M RP10 IIC Board View: https://drive.google.com/open?id=1Lx0AofY9eI34mGY3RbgNDSV5IgEUf5cS RP11A IIC Schematic: https://drive.google.com/open?id=1_KWgnYKephAlJAnfH8IL9El8qHdo5nji RP11A IIC Layout : https://drive.goog...
by jrb32
Thu Nov 14, 2019 7:24 am
Forum: Vintage Amps (Before 1991)
Topic: Tone stack caps in C+
Replies: 2
Views: 519

Re: Tone stack caps in C+

Interesting! Maybe a loose connection fixed itself when you straightened them upright. I doubt the silicone wouldn't do anything it's there for vibration reasons as you mentioned. It would indicate that the tone stack area is a good place to look into as I know you had a bit of a voltage spark aroun...
by jrb32
Fri Nov 08, 2019 1:39 pm
Forum: Vintage Amps (Before 1991)
Topic: Mesa boogie clone
Replies: 1
Views: 861

Re: Mesa boogie clone

Without a schematic or spending ages tracing it out you're on your own really! Sorry mate.
by jrb32
Fri Nov 08, 2019 1:32 pm
Forum: Vintage Amps (Before 1991)
Topic: Putting together a Mark III Guide
Replies: 37
Views: 6901

Re: Putting together a Mark III Guide

chipaudette wrote:
Fri Nov 01, 2019 9:08 am
All of the links appear to be broken. 404!
Hey sorry I've not been on here for ages! Are the links really not working? Can people confirm and I'll try and fix them or stick up some alternates. PM me if you're still having problems.

Cheers,

Jon
by jrb32
Thu Aug 01, 2019 4:35 am
Forum: Vintage Amps (Before 1991)
Topic: Mark llB - difference between early and late models
Replies: 12
Views: 3514

Re: Mark llB - difference between early and late models

Amazing info! Any chance you could upload any detailed pics of the RP8 and RP9 boards? Since my earlier post on here I've managed to trace and map out the RP10 and RP11 boards for the IIC/C+ and all the Mk III boards along with schematics. Trying to document and date the development of the early Mk ...
by jrb32
Sun Jun 02, 2019 4:58 am
Forum: Vintage Amps (Before 1991)
Topic: MKIIC+ ++ mod
Replies: 3
Views: 1248

Re: MKIIC+ ++ mod

No idea I'm just a repair monkey! I can figure out how to fix things or implement circuitry but understanding the exact difference certain values of components will make or design an amp... sorry! One day maybe :) I am on the understanding that putting the 100K in is indeed optional, BUT it does hav...
by jrb32
Fri May 31, 2019 2:05 pm
Forum: Mark Series
Topic: Original Mark II C+ vs. Mark II C Conversions, Any Differences?
Replies: 4
Views: 1214

Re: Original Mark II C+ vs. Mark II C Conversions, Any Differences?

Depends on the board. If the IIC has an SP11A or RP11A (from about September 83 onwards) then a converted IIC+ will be IDENTICAL to a factory IIC+ in every physical way. Seriously. 100%. No question. If it has an SP10A or RP10A (the early IICs before this) then it will be identical from a circuit po...