1176 Plosives: looking for Rev A schematic or high res internal shots
- Thread starter Neeno
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kazper
Well-known member
Anyone have the better scan of the schematics, the link is broken. If you can send them to the group emails that would be great!
Another interesting thing is the missing RC network off the attack time control.
Kaz
Another interesting thing is the missing RC network off the attack time control.
Kaz
kazper
Well-known member
ilfungo said:
I'm not up on the newer revision A Pcb's, but Mnats A version is basically what your after.
The original A version 1.0 PCB layout was done to the first 1176 schematic, read his post in this thread. His newer boards have slight revisions to get you to A.
Kaz
haima
Well-known member
kazper said:
+1
I stitched together la-2a's scans while working on the V1.2.5 boards: http://mnats.net/files/1176_125.pdf
I've linked the document from my Rev A page as well.
I've linked the document from my Rev A page as well.
martthie_08
Well-known member
this probably comes two years late, but if you look at the schematic you will note that Cx6 is not present, so just jumper this (with a bare wire or 0Ω resistor, not 47kΩ).
On the V1.1 boards, Cx6 has already been omitted...
Neeno said:Ok guys, after comparing the various schematics (original 1176, rev A and Mako's rev A) I came across a bunch of values that should be the ones used on the real Blue Stripe. Of course those have not been checked with a real unit, so, please if you own an original rev A Blue Stripe check the values and report back !!!
I did this as an experiment, you don't need to change anything if you followed Mako's BOM, in fact his revision sounds really good as it is !
And well, Mako, thank you very much for the rev A !!!! A great board, an easy build, just lovely !
I've got the values comparing the Rev A schematic to the one used by Mako (Original 1176) which are the ones between parenthesis.
R6 = 2.2M (560k)
R7 = 2.2M (560k)
C6 = REMOVE (33pF across R16)
C6a = ADD 68pF across R7)
R11 = 9.1k suggested by Ed Anderson (10k)
R12 = 2.2k (1k)
R16 = 100k (47k)
R17 = 4.7k (8.2k)
C9 = 6.8uF (47uF)
R30 = 150k (120k)
C11 = 10pF (47pF)
Rx14 = REMOVE (820k)
Cx6 = JUMPER (6.8uF)
R76 = 10k (8.2k)
R54 = 1.2k (470r)
C27 = 0.012uF (0.022uF)
Ratio Board
=======
R22 = 47k (56k)
R19 = 68k (130k) NOTE: If you're using the great Hairball PCBs R19 is marked as R8 on the documentation
R78 = 47k (NOT PRESENT) NOTE: R78 is marked as R10 on Hairball PCBs
R64 = 2.2k (1.2k)
LINE AMP MOD
=========
This mod adds a resistor (3.9k) in series with a capacitor (1000pF) and it should be connected from the (-) of C9 to the junction of WHTRED - R32. Take a look at the picture.
sorry to revive this over two year old thread, but in case someone stumbles over it:
the above collected information comes in very handy for anyone wanting to mod their V1 Rev A boards (V1.1 31.01.09 in my case) to the current V1.2.5 schematic values that are what you get when you currently order a board from mnats.
There is one minor mistake in the above information:
R76 = 10k (8.2k)
this should be
R76 = 18k (8.2k)
thanks for all the hard work everybody has put into this project!
EDIT: one more addition to this list, on the ratio board,
R1 (R58 on schematic) = 120 (180)
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