Scannermax 506s

[absolom7691]

To avoid any mishaps, I ordered a beefy PSU for my modded amps with ample capacitance and RF filtering. My PSU finally arrived and I will be testing out these scanners on Steve's boards, side-by-side against my DT-40s. Of course, I need to wait for a replacement blue diode which I popped over the weekend *grrrrr*. Once that arrives, I will be testing these out.

[f150trk21]

To avoid any mishaps, I ordered a beefy PSU for my modded amps with ample capacitance and RF filtering. My PSU finally arrived and I will be testing out these scanners on Steve's boards, side-by-side against my DT-40s. Of course, I need to wait for a replacement blue diode which I popped over the weekend *grrrrr*. Once that arrives, I will be testing these out.

Where did you get that psu?

[absolom7691]

Where did you get that psu?

Got from here (thanks Edison):

http://connexelectronic.com/product_...roducts_id/141

It's got a pretty small footprint and specifically designed for audio A/B and D amps. Plenty beefy enough for some scanners. Not the fastest on shipping (3 weeks), but it looks like a really nice unit.

[mixedgas]

Ok, While your waiting for the Blue Diode... Get 2 motherboard jumpers. Use them to ground the input of one amp. The inner two pins of the signal connector are ground, the outer two are the differential inputs. I have marked a potentiometer in the attached image. Its the DC offset pot. Its wiper is the center pin in the row of three on the back of the board, under the pot itself.

Using a DVM, adjust the pot to match your galvos offset to zero while the inputs are shorted. I usually set them to within 10-20 mV of zero. It will swing either side of zero, inverting polarity as it crosses thru the zero spot. One DVM lead goes to ground , the other is held onto the wiper while you adjust. Do NOT allow the probe to slip to the other two terminals while adjusting. +/- 10 mV is excellent, +/- 20 mV is good, etc.

If your hand is shaky, solder a short jumper onto the wiper pin and use that. Remove the jumper when done, this is not an adjustment that drifts very much.

Redboard offset pots are really not that good at adding a large position offset to an image. However they really are good for canceling offset of the Galvo sensor.
This will give you good linearity.

Do this for both the X and Y galvos if you are more then say 50 mV off.

Steve

[absolom7691]

Ok, While your waiting for the Blue Diode... Get 2 motherboard jumpers. Use them to ground the input of one amp. The inner two pins of the signal connector are ground, the outer two are the differential inputs. I have marked a potentiometer in the attached image. Its the DC offset pot. Its wiper is the center pin in the row of three on the back of the board, under the pot itself.

Using a DVM, adjust the pot to match your galvos offset to zero while the inputs are shorted. I usually set them to within 10-20 mV of zero. It will swing either side of zero, inverting polarity as it crosses thru the zero spot. One DVM lead goes to ground , the other is held onto the wiper while you adjust. Do NOT allow the probe to slip to the other two terminals while adjusting. +/- 10 mV is excellent, +/- 20 mV is good, etc.

If your hand is shaky, solder a short jumper onto the wiper pin and use that. Remove the jumper when done, this is not an adjustment that drifts very much.

Redboard offset pots are really not that good at adding a large position offset to an image. However they really are good for canceling offset of the Galvo sensor.
This will give you good linearity.

Do this for both the X and Y galvos if you are more then say 50 mV off.

Steve

Thank you, Steve. I'll check out the adjustments when I get home and make any necessary tweaks. I might use my friend's oscope instead of a voltmeter.

[f150trk21]

Hey Steve

Do I need to do that with my amps, Bill did tune mine.

[mixedgas]

Hey Steve

Do I need to do that with my amps, Bill did tune mine.

Most likely not if Bill tuned the amp.

I zeroed all of them before shipment to Bill.

For some one doing a review, setting zero and then checking the linearity with a scope might be a critical step. For most users, it will be darn close as tuned.


Steve

[mixedgas]

Thank you, Steve. I'll check out the adjustments when I get home and make any necessary tweaks. I might use my friend's oscope instead of a voltmeter.

OK, Revised WHAT IS WHAT PHOTO attached.

[absolom7691]

OK, Revised WHAT IS WHAT PHOTO attached.

Awesome. Thanks!

[mixedgas]

It is STRONGLY recommended that before one makes ANY adjustments on a calibrated REDBOARD that one does the following simple procedure:

Each REDBOARD has a unique tuning signature. Other then a slight touchup of Servo and LF Damping, a REDBOARD should run very well as received.

RETUNING IS A USER PEROGATIVE, FOR ADVANCED USERS.

IN THE HIGHLY UNLIKEY SCENERO THAT YOUR REDBOARD NEEDS A RETUNE, FOLLOW THE PROCEDURE BELOW BEFORE TUNING.

0. DO NOT "ZERO" ANY POTENTIOMETERS. POPULAR TUNING INSTRUCTIONS ON THE WEB DO NOT COMPLETELY APPLY TO REDBOARD.
FOR EXAMPLE: REDBOARD NEEDS AT LEAST 8 TURNS CLOCKWISE OF SERVO GAIN AND LF DAMPING FOR INITIAL STABILITY DURING TUNING.
WALKING THE TRIANGLE FROM ZERO, STATED IN A POPULAR TUNING PDF, IS NOT APPLICABLE TO THIS BOARD.

1. Observe precautions for anti-static conditions before probing your REDBOARD.
2. If you disconnect the REDBOARD from all the wiring harness and flip it over, you will see a row of solder dots under the trimmer potentiometers.
3. Make sure there is NO wiring connected at all to the REDBOARD other then a ASTAT CLIP if used.
4. Using a good quality Digital Ohm Meter, With the RED LEAD on the solder dot nearest the board edge, measure the resistance from the pin nearest the board edge to the wiper for the following potentiometers:

A. SERVO GAIN
B. LOW FREQUENCY DAMPING
C. HIGH FREQUENCY DAMPING
D. ERROR LIMITER
E. DAMPING BREAKPOINT

4. MEASURE NO OTHER POINTS, I AM REASONABLY SURE THE BOARD WILL NOT BE DAMAGED WITH A GOOD QUALITY DVM AT THESE POINTS.

5. RECORD THESE MEASUREMENTS. IF NEED BE, THESE WILL HELP YOU RESTORE INITIAL TUNING.

6. NO TWO BOARDS ARE THE SAME, ESPECIALLY CUSTOMIZED BOARDS FOR 5 mm MIRRORs. ONE CANNOT TUNE A GALVO AMP BY RESISTIVE MEASUREMENTS ALONE! WHILE I GET CLOSE USING A INITIAL SET OF STOCK MEASUREMENTS, TUNING A SECOND AMP BY RESISTIVE TRANSFER ONLY WILL NOT HELP YOUR FRIEND"S IMAGE QUALITY.




I strongly suggest never changing tuning done by William R. "Bill" Benner.

CHANGING THE "AGC" POTENTIOMETER WILL RESULT IN THE NEED FOR A COMPLETE AMPLIFIER RETUNE!

DAMPING BREAKPOINT IS BEST LEFT ALONE AS WELL!
Steve