JLH Monoblocks...PSU boards are different Mk's....

[tonewheelkev]

Hi Folks
....finally get onto recapping/fettling these 2 JLH Monoblocks, and just noticed that the PSU boards are marked as : HART 1150 and HART 1150-2
(I've attached a rather poor pic.)

This might be one for one of the JLH aficionados 'out there', but hoping to discover the essential differences between the 2 vintages, as I'd like to bring 'em both up to 1150-2 spec....if that's possible.

(I'm a bit obsessive...possibly autistic about things like that!! )

 

[PRR]

> to discover the essential differences between the 2

Blink comparator - Wikipedia

 

[tonewheelkev]

> to discover the essential differences between the 2

Blink comparator - Wikipedia

Thank-you?????

 

[blu_glo]

if you put the two side by side are any components different or moved?
Same for PCB traces? should not be too difficult to spot differences (if any)

 

[tonewheelkev]

Differences...

Thanks blu_glo...haven't spotted any differences to the track (so far!)


Have noticed some plain wire links on Mk1 board have been replaced by 1ohm resistors on Mk2. This is a little inconvenient, as these are located under the footprint of the reservoir caps!!

 

[tonewheelkev]

Think I've sussed it now!
2nd revision has an 'extra' 15v output on board for powering 'extras'...which are irrelevant for me anyway!
Appears that the 1ohm resistors that I'd wrongly identified are in fact zero ohm links....

 

[blu_glo]

Ah, OK, so theres quite a brace of extra components on one PCB?

 

[tonewheelkev]

Ah, OK, so theres quite a brace of extra components on one PCB?

No...colours apart, and the zero ohm resistors vs wire links...they're pretty much identical...but for the presence of skt2 on the revised edition.
As I'll be using them as monoblocks...so wont be needing the 15v skt2 anyway!
Thanks again!!

 

[tonewheelkev]

Just spotted some changes to the pcb track layout beneath the 4 x large rectifier diodes.
Rev.2 simplifies orientation of said diodes....meaning they now all face in same direction!
Doesn't appear to bring any component variation....