Spooky and Hellraiser SMD 60W amps (Wolverine compatible IPS)

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#762
codegen said:
its tempting to say i have got something wrong with the output section.
Click to expand...
Not much really, other than this missing link at R1, R3. Same on the negative side.
1740324998113.png

Is there anything showing up on an oscilloscope?
 
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#763
@jwilhelm RV1 is set to 500 ohms, measurement between PD+ and ND- is 0.0v, but i also just noticed that there where no voltage into the IPS board - and while writing this i see nattawa pointing this out. This connection is missing and therefor i have near no voltage without IPS board, and 0v when its attached. I will try to do a fix for this to see if it helps 😎
 
#764
So there is now power to the IPS board, but really no change, Still experiencing same issues whenever IPS board is connected.
Wolverine IPS:
  • Voltage +- 7.2v on IPS
  • Voltmeter shows 0v between PD+ and ND-
  • GND -> ND- is 7.1v
  • GND -> PD+ is 7.1v
  • Output of outputstage is 5.4v DC (Measured with oscilloscope, no oscilation seen on the output)

Symasui IPS:
  • Voltage +- 12.2v on IPS
  • Voltmeter shows 3.2v between PD+ and ND-
  • GND -> ND- is - 1.2v
  • GND -> PD+ is +1.9v
  • Output of outputstage is +110mV DC

Symasui IPS clearly looks much better(something must be wrong with the Wolverine IPS :-S), but with the bulb in series it have a high light output and power used from grid is 50w.
Measuring between TP6 and TP1 shows 62mV, while TP6 to TP11 shows -72mV. Which is quite high considering that the RV1 pot meter is turned all the way upto 500 ohms.
 
#765
When we built the Slewmasters we tested the output board standalone. We put a 12k resistor from V+ to ND+ and another from V- to ND- and powered it up like that to verify bias current was okay.

For current to flow in the output stage it should need to see around 3.6V (6 pn junctions) between PD+ and ND- when current starts flowing in the output transistors. Measurements to ground aren't really useful here. Turning the bias trimmer pot should change this voltage reading. As the voltage rises, output current rises. If you can't get output stage under control, disconnect a leg on R7 as a test, that should turn the output stage bias off completely.
 
#770
jwilhelm said:
When we built the Slewmasters we tested the output board standalone. We put a 12k resistor from V+ to ND+ and another from V- to ND- and powered it up like that to verify bias current was okay.

For current to flow in the output stage it should need to see around 3.6V (6 pn junctions) between PD+ and ND- when current starts flowing in the output transistors. Measurements to ground aren't really useful here. Turning the bias trimmer pot should change this voltage reading. As the voltage rises, output current rises. If you can't get output stage under control, disconnect a leg on R7 as a test, that should turn the output stage bias off completely.
Click to expand...

Thanks. I tried to put a 12k resistor between V+ and PD+, and V- and ND-. Outputstage now seem to be acting like it did with IPS mounted. Voltage reading between PD+ and ND- is now 3.1v, however turning the bias trimmer pot does not change anything - even screwed it all the way to 0 ohms just to see what happened

Protection bulb is still connected, so i only have about +-13.7v on the board now(bulb(60w) is lighted and power drawn from mains are about 50w). Dissasembled just now to verify its actually MJE340 vbe`s mounted 🤓
 
#772
Hi,

Attached is layout for SYMASUI and SPOOK IPS boards. For now those use THT BJTs, but I plan to change few elements to SMD parts.
Can You check if those layouts are correct (for ex.R2/C2 SPOOK position… and others)? Maybe some changes need to be made.


SPOOK
-> for now SERVO is AD744, but will change it to TL062BCDT (already bought for original boards)
-> QTLP690C leds replaced with LTST-C194KRKT (same parameters)
-> where to place test points for troubleshooting?
-> Q1/Q2: I used TO-126 footprint; I was thinking about using KSC2682/KSA1142 in those position; also it’s possible to use common heatsink for Q1/Q14, Q2/Q15 so maybe KSC1845/KSA992 can be used with some sort of custom mounting clip; is KSC2682/KSA1142 good choice for Q1/Q2?
-> Clead capacitors; how to calculate it’s value properly / 2pF is total capacitance of pcb track and capacitor?
-> BOM is not ready, layout need to be checked first.
-> which resistors need higher power rating?

SYMASUI
-> where to place test points for troubleshooting?
-> which resistors need higher power rating?
-> any other sugestions?

Want to send those PCBs for fabrication soon, so any input will be appreciated 😊
 

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#773
Spooky PCB (a 5 minute quick and dirty design check):
The schematic has errors when running the electrical rules checker.
The PCB layout has 245 errors and 148 warnings when running the design rules checker. Some of these errors are related to not having your libraries locally. These issues will need to be fixed before sending the gerber files to a PCB manufacturer.
Some resistors have capacitor footprints. Many components not aligned properly with respect to pcb tracks.
KSC2682/KSA1142 are obsolete.
You'll need to configure the specific design rules for the board.

Symasui PCB (a 5 minute quick and dirty design check):
The schematic has errors when running the electrical rules checker.
The PCB layout has 136 errors and 70 warnings when running the design rules checker. Some of these errors are related to not having your libraries locally. These issues will need to be fixed before sending the gerber files to a PCB manufacturer.
Some resistors have capacitor footprints. Many components not aligned properly with respect to pcb tracks.
You'll need to configure the specific design rules for the board.
 
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