Trouble after speedball upgrade

[antoineestephan]

Hi again
Please don't give up on me guys, I need help
I went and bought some ordinary red LEDs and replaced my dead ones, and guess what, both my LEDs lit up.
I started with voltage readings, T1 was 88V T5 was in the 90s, I didn't write it down but when I touched the LED at A8 it went off immediately.
So I started retracing every wire in my crack, and I noticed that I had contact between A7 (red wire) and the ground, which struck me as odd, even though I have exactly followed the manual, I double checked.
I retraced backwards steps and found that the red wire from B8 and A7 is connected to terminal 4 on the transformer which is the 0V, and this same terminal is connected to T14 (ground), which sounded odd to me, red wire and black wire on the same terminal.
Need help please

[sjeffrey]

You can't replace the LEDs with just normal ones.
The LEDS are HLPM 6000.  At least it seems you probably found your issue.  Get some replacement LEDs (assuming they are in fact dead), fix the A7 connection and try again.
I don't have the manual with me but from memory T14 does have a red and a black wire connected to it.  I inquired about it and basically it is black because they don't have teflon white wires so they chose black over red.

[antoineestephan]

Now my readings are as follows
T1.  88,      T2.  149,    T3. 0,   T4.  152, t5. 94, T6.  0, t7. 106, t8. 0, t9. 110, t10. 0, t11. 0, t12. 0, t13. 155, t14. 0, t15.  173, t20 0,  t21.  192
A1.  93, A2. 0, A3.  1.65, A4&A5. 0, A6.  87, A7.  0, A8.  1.65, A9.  0
B1.  87, B2.  152, B3.  104, B4.  93, B5.  154, B6.  109, B7.  0, B8.  0.
Now these are much better readings, especially since they were not done with the regular LEDs, the worst readings I got now probably are T5 94V instead of 75, and B4 93V instead of 75.
Any thoughts.
And please chip in don't give up on me, I'm getting better.
Nice day all!

[antoineestephan]

You can't replace the LEDs with just normal ones.
The LEDS are HLPM 6000.  At least it seems you probably found your issue.  Get some replacement LEDs (assuming they are in fact dead), fix the A7 connection and try again.
I don't have the manual with me but from memory T14 does have a red and a black wire connected to it.  I inquired about it and basically it is black because they don't have teflon white wires so they chose black over red.

Thanks, I know that but I couldn't find any, and I found a post where PB said that "he thought any red LED would work, although he wasn't sure how much impact on sound quality it would have"
And since I live in Lebanon and I have to order from USA, that means also about a month to wait, so I had to try.

[Grainger49]

Grab some generic Red LEDs to troubleshoot.  Then order some HLMP 6000s to finish the project.  Be certain not to button up anything you will need to pull out when you get your HLMP 6000s.  The trick with them is the steady voltage drop with differing voltages across them.

[antoineestephan]

That's exactly what I did, now my crack is working wonderful, if the original LEDs would be an improvement in sound quality, oh! wow how sweet can it get?

[Paul Birkeland]

The LED's on the 9 pin socket can be changed to resistors for troubleshooting.  This is not the case for any other LED's in the amp, if you use resistors on the PC boards in place of the LED's, the boards will not work.

470 Ohm resistors can be used for the 9 pin socket LED's.  If you find a value in the range of 450-500 Ohms, you'll be OK.  Wattage isn't exactly important, 2/100 of a Watt is sufficient.

[antoineestephan]

The LED's on the 9 pin socket can be changed to resistors for troubleshooting.  This is not the case for any other LED's in the amp, if you use resistors on the PC boards in place of the LED's, the boards will not work.

470 Ohm resistors can be used for the 9 pin socket LED's.  If you find a value in the range of 450-500 Ohms, you'll be OK.  Wattage isn't exactly important, 2/100 of a Watt is sufficient.

Hi,
I just replaced my broken LEDs with ordinary generic red LEDs, now my crack with speedball is actually working, very good, and the sound quality is there, if replacing the generic LEDs with HLMP6000s would still improve the sound quality I'd be even happier.
Just do you think that I could harm my amp running it like this?
Thanks

[sjeffrey]

I would at least get some 470ohm resistors, they should be easy to find.

[Mike B]

If it works, don't fix it.

Get the proper parts and fix it the right way.

Measure the voltage, if it's near 1.5 it's fine.

[antoineestephan]

It's actually working ok I only hear the slightest hiss when listening at really low low levels. Something like the hiss you would hear on tape players, the hiss doesn't go higher with more volume, other than that everything is fine.
The voltages I got are 1.65V at both A3 and A8, both well within the 15% rule, so I think I'm ok for now.

[Paul Birkeland]

1.65V is a little high.  The actual voltage across the HLMP-6000 is very, very close to 1.57V (which is a big part of why we use them).  Having 1.65V there won't hurt if your T1/T5 voltages are OK.  If you used those on the Speedball PC boards, however, things would get a little out of whack. 

-PB

[Mike B]

Order up the correct parts and solder them in at your leisure.  When you are nice and relaxed and not thinking about 10 zillion other things.  Those cathode diodes are the hardest part of the kit.  Getting those tiny parts into that tiny space between the center and the outer pins.

Take your time and do it right.  Those teensy-weensy parts are hardest parts I have dealt with yet.  One sprung out on me when I was building mine and hit the floor.  I thought I'd be ordering another because I couldn't find it.  Looked just like all the other itty-bitty bits of insulation laying there too.  Finally found it.  Un-crushed by the chair wheels or my shoes -

[antoineestephan]

1.65V is a little high.  The actual voltage across the HLMP-6000 is very, very close to 1.57V (which is a big part of why we use them).  Having 1.65V there won't hurt if your T1/T5 voltages are OK.  If you used those on the Speedball PC boards, however, things would get a little out of whack. 

-PB

My T1 reads 88V, and T5 94V, so they seem to be on the high side.
But I'm using my crack with speedball and it's sounding great with the Westinghouse 12AU7 that came with it. But I'm hearing an audible low level hiss with a newly bought russian Genalex, that was supposed to be an upgrade, it's like the hiss that you could hear on cassette tarp decks, for those who remember them.
Anyway would I harm anything inside my crack if I continue to use it this way, should I stop using it until I replace my LEDs?

[Paul Birkeland]

88V and 94V isn't too far off, I'd say you're OK.