[BUILD] 1176LN Rev D DIY

[Echo North]

Do you have yellow and orange tied together?  I would also check every resistor value and cap in your output amp section.

 

[safe as milk]

hi
thanks for the reply mike..on this unit i have a 5002 with orange/ yellow tied
on the other one i get the same with the cinemag...
i've nearly replaced all the resistors & caps in this section...
if that doesn't get it i'll post up again!

is hfe important at all in the amp section?

cheers

 

[Echo North]

hi
thanks for the reply mike..on this unit i have a 5002 with orange/ yellow tied
on the other one i get the same with the cinemag...
i've nearly replaced all the resistors & caps in this section...
if that doesn't get it i'll post up again!

is hfe important at all in the amp section?

cheers

HFE should not be important.

Also make sure your output pot is wired correctly.

 

[number2]

hi
number 2 the docs say-

Insert the appropriate 5 x 20 mm fuse in the fuse holder
- 1/8 Amp Slo-Blo for 120V or 1/16 Amp Slo-Blo for 240V AC line voltage.

OK absolutely no substitutions then? the closest we got at radioshack is 1/2 amp slo blo and .315 amp fast-acting. I guess either would allow too much current to pass?
sorry for the theory but this practical example is a great way to learn for me.

 

[safe as milk]

number2
im sure you'll be fine with the 315mA fuse.

ok i have now replaced all resistors & caps in the output section
and no change...
apart from the drilling on Q7-10 were there any other mods for this 1st board batch?
ill go through the early version thread again now...

cheers

 

[Echo North]

C12 and C 10 are orientated w/ the correct polarity?

Do you say you have two units, one with a Cinemag and one with an EA-5002?  Are both behaving the same?  I'm trying to weed out that it may be a bad output tx.

Mike

 

[safe as milk]

rollocks....my boards are a pair of rev 1

but i also have a new rev2.2 half stuffed
and i did what matahaze did wiring the output trafo to rev2 wiring
as i have covered the pcb writing with screw terminals
finally Q6 gets hot 8)

going to do all sorts of tests now!

 

[Echo North]

rollocks....my boards are a pair of rev 1

but i also have a new rev2.2 half stuffed
and i did what matahaze did wiring the output trafo to rev2 wiring
as i have covered the pcb writing with screw terminals
finally Q6 gets hot 8)

going to do all sorts of tests now!

Ah ha!  That should fix you!

 

[Stagefright13]

Cool! I did the same thing once. The rev 1 sounds just the same so ya know.... Great!

John

 

[usekgb]

I did the exact same thing with both of mine!  Funny.

Cheers,
Zach

 

[safe as milk]

i dont feel quite so bad now you guys have fessed up to the same user error

but i've taken one of the now working rev1 boards out of the 1176 and
put it back into my stereo/rotary box
and im getting no needle at zero in GR mode, no compression & therefore
cant set the Q bias etc...etc

ratio board seems good, dc at pad 21 is between 2- 6v

when i power down the needle goes up to zero in GR mode!!!

what on 'earth' does that mean?

cheers

 

[Stagefright13]

Wiring problem I would think.

 

[safe as milk]

yeah defo my wiring!

in this dual unit i thought it might be a meter switch board so i removed that
and did point to point but no change...

so i swapped the known good main card to the left channel only to get exactly the same error.

this is the box i've been chasing my own tail on for well over a week now...
thats why i put together the 1176 over the weekend to test the cards in which worked well.

cheers

ps i just started reading this thread again from the start & saw my post saying i
bought some trafo's of eanderson in 2006, thanks again....
here i am finally trying to send audio through them 6 years later....
i wonder who holds the record for builds/parts sat on the shelf the longest ;D

 

[usekgb]

yeah defo my wiring!

in this dual unit i thought it might be a meter switch board so i removed that
and did point to point but no change...

so i swapped the known good main card to the left channel only to get exactly the same error.

this is the box i've been chasing my own tail on for well over a week now...
thats why i put together the 1176 over the weekend to test the cards in which worked well.

cheers

ps i just started reading this thread again from the start & saw my post saying i
bought some trafo's of eanderson in 2006, thanks again....
here i am finally trying to send audio through them 6 years later....
i wonder who holds the record for builds/parts sat on the shelf the longest ;D

I bought my transformers in the original Ed Anderson group buy, probably about the same time.  I soldered everything to my boards, and then shelved the whole thing.  I bought a stereo case from Parusha about the same time as well.  I finally finished putting it all together a month or two ago.

When I power mine down, my meters go all the way to the top, and then settle down to the left as the caps discharge.  I don't think this is unusual.  The one thing that I wish the rev 1 PCB's had was the jumper to take R44 out of the circuit!  That sure would have been nice!

Cheers,
Zach

 

[safe as milk]

hi
that's good to know i'm not the only slow one when it comes to finishing projects...
my old original rev d's do that discharge thing too...
i got to the route of the problem this afternoon...slight lift on a release pot pad
on both ratio boards
i think this is from where i've got them shoved in right up againt the VU bezels
it's been a bit of a battle as ever but sonically worth every minute 8)1

i used bbc input trafo's(2:1) on the front end & i prefer them to the 1176 i finished
on the weekend with the altran from ed...maybe the distortion trimmers have landed
in a better place....which is good, cos i aint setting them up

cheers & thanks again to mnats & mike for your ongoing help on this project/thread

 

[dandeurloo]

Guys, I have some strange noise in both of my channels of my Stereo 1176.  I have posted a screen shot.  I wonder if any of you guys could help point me in the right direction.  For trouble shooting this or if any of you have the same noise.  I basically turned the input and output up 100% and just recorded the noise back into the DAW.  So its just per amp noise.  The 2.5k spike is on both channels and the both have the same ark.

 

[PeterL]

sr1200, I finally was able to work on this today and I am confused by my results. I tried what you suggested and checked the voltage from the power transformer and going into my IEC socket. I get a reading of 0 out of the left side (looking into the chassis) and -0.4 on the right side, which has the metal tab visibly connecting to the fuse holder. I should note the IEC is plugged into a reliable power source and the cable works with other equipment.

The fuse is still not blown and all components including capacitors and resistors look just as I put them in there. Nothing is bulging or cracking. Still no signs of life. The power transformer appears fine, but I know looks can be deceiving. Maybe I blew it. Should I purchase a new pair of PT's from Hairball and try them out?

Peter, with your meter in AC mode, check the voltage going into your IEC first. (both sides of the fuse)  If your reading is good there, if the reading it good there, remove the transformer from the board and check the leads from the transformer.  If you're getting NOTHING from the transformer, i guess it might be possible the transformer blew, but I would have to think that's a rare occurrence (but does happen).  If you're getting proper voltage from the tranny, time to check the PS and your VR (and caps... are any of them looking a little bulbous or cracked on top?)

 

[sr1200]

Peter. change the fuse. weather you think its blown or not.  At the IEC after the fuse you should still be getting 110-120VAC(in the us/can/japan).  And make sure your meter is set to AC not DC.

 

[usekgb]

I finally got around to trimming down the posts on my pots, installing knobs, and hooking the lights up on my vu meters today.  For the lights, I did something pretty simple.  I ran an 820 ohm 3 watt resistor from one leg of the power transformer secondary in to a diode to half-wave rectify the voltage.  then, I hung a 2200 uF cap of the + and - terminals of the meter to smooth the voltage.  The negative terminal ran back to the center tap of the power transformer secondary.  I read 5.9 volts on the LED's in the meter.  Perfect!  Then, I just jumped from one meter to the other meter in my stereo unit.  Total power draw from the lights in the meters is 40mA. 

I can finally see my meters in the dark.  Yay!

Cheers,
Zach

 

[safe as milk]

usekgb
it's always nice to have some lights...i ran my led's the same but no cap or diode?

dandeurloo
could that be the oscillation that some people talk about with the output cranked?

my stereo unit is still not a happy camper
the left ratio board is acting like a stepped output attenuator!!!
needle is pegged right at 20:1
zero at 12:1
-6    at 8:1
-12  at 4:1

vu shows the same reductions in output mode.
so it's changing my output gain for me :-[
but more importantly......no compression.

i know it's my wiring still so i'll keep hunting ;D

now i wonder which ladder i should try first


has anyone ever done point to point of the ratio on a rotary switch before?