Mr Bills Mod Help on a classic SL ID

[keith777]

Hi guys.
it has been a few years since i done a MR bills Mod to a Whites Classic machine.
anyways. i have reasonably picked up a classic SL with the ID Meter on. i am going to do the Mod on it. i opened the case today to check it's insides out. on looking at the board 3 resistors have already been replaced.

resister R7 51 Ohms 1% tolerance.
resister R56 100 Ohms 5% tolerance.
resistor R18 1100M Ohms 5% tolerance. i am not sure why this resistor has been replace. or what the original resistor value was. not mentioned in the MR Bills Mod.

thanks in advance guys....

[Carl-NC]

R57 was replaced, not R18, and it's 47 ohms, not 1100M. The original value (in the Classic 3) is 10k. It is in parallel to the 10k disc trimmer and 47 ohms seems very low to me.

[keith777]

this is the document that i have for the Whites Modification.


Whites Classic, II, III, ID, and IDX Modifications

Seeing that I have got out of the metal detecting busness. I thought I would pass this on to you all.

Be very carefull unsoldering the componets. Distroying the circuit traces is very easy to do.



"Ground balance" Remove VR1 Trimmer off the board. Replace with a 50k linear taper, single turn potentiometer.

"Threshold" Remove VR4 trimmer off the board replacing it with a 100k linear taper, single turn potentiometer.

Mount these potentiometer’s externally on the top of the case.

replace R25 for a 1K resistor and thus gain more sensitivity.

Replace resistor R24 with a 2.2 Meg. You could have either a 470k or a 1.5 Meg there depending on when the unit was manufactured.

Check resistor R7. If it’s not a 51 ohm resistor = Green, Brown, Black, Gold. replace it with one of that value. It’s most likely a 100 ohm from factory. Later manufactured units had 51 ohms.

For potentiometer wiring, I use flat multi wire such as type used in computers for component connection to the board. I cut a 2 wire, 7.5” piece for the 50k ground balance pot, and a 3 wire 7.5” one for the 100k threshold pot. I secure these wires with a wire tie to the head phone & speaker wire near the connectors. I used one other wire tie to secure the pot wires together up near the pots.

Caution. Be sure that the pot closest to the end of the case doesn’t short out against the installed board components.

S.A.T changes. R32 220k resistor can be changed out. Raising the value slows the SAT. I have been installing a 375k or 360k running it through a toggle switch with the 220k. Giving a high & low setting of the SAT. One could use a potentiometer for variable results.

If your detector uses a ID meter, open the meter case, and replace resistor R28 (3.9 meg) with a 10 meg resistor. This aids in increasing the meter response depth.



R32 resistor is 220K for stock SAT, 375K for the high end. 220K--Fast SAT retune, 375K --- slow retune.

Remove 220K, find a 400K pot. I happened to find a 500K in my parts box. One wire goes to the center pin on the pot and the other goes to one of the outside pins on the pot. I can't find my drawings. So if I am correct the center pin on the pot gets wired to the resistor pad with the circle. You will have to wire the outside pin so when turning the pot clockwise the value will drop to 0K, when turned back counter clockwise the value will be the highest. At 500k, the detector is almost a non-motion machine, at 0K it retunes really fast. Note when having adjustable SAT and making an adjustment, you'll need to make a slight Threshold adjustment, they are tied into each other.
for the SAT potentiometer a 400K linear pot probably ideal. though very hard to find, next best would be a 500K, easy to find, its what I used.

[keith777]

is that resister numbered 57 on the board. have i been looking at it wrong.

[Carl-NC]

is that resister numbered 57 on the board. have i been looking at it wrong.

Yes.

[keith777]

replacing R57 was not mentioned in the MR Bills Mods. why do you think that it has been replaced? should i replace R57 back to the original 10k resistor.

[keith777]

i have found a photo of a board with the original R57 resistor still in place on the board, but i can not make out the color bands very well.

[kt315]

sch of IDX

[Carl-NC]

On the IDX it's 5.1k, on the Classic 3 it's 10k, and it's not used in the Classic 4. It's not all that important, it just determines the trim range for the disc control for setting a consistent disc point.

[keith777]

so do you think that i should just leave that replaced resistor in on the board. or swap it out for a 10k resistor?
thanks in advance....

[Carl-NC]

I would first see how the disc control is behaving. If it seems correct, leave it alone.

[keith777]

OK. many thanks..........

[keith777]

I would first see how the disc control is behaving. If it seems correct, leave it alone.

Hi again Carl.

i have done all the mods to the machine now. including the ID meter one. all seems to be working ok from what i can tell. pic below. i tested to see how the disc control was behaving like you suggested. i am not familiar how and ware coins should be reacting on this machine, but if you look at my second photo. i tested all these coins on two setting on the disc control. first on the "Ring Range Presetting" all coins were being picked up OK. then on the "Coin Range Presetting" not all the coins were being picked up. only the coins in the top row of the photo. does that seem about right do you think?

[kt315]

maybe you need direct hit but are not able to seek up??

Whites Classic, II, III, ID, and IDX Modifications - Geotech Forums (geotech1.com)

[kt315]

Hi again Carl.

i have done all the mods to the machine now. including the ID meter one. all seems to be working ok from what i can tell. pic below. i tested to see how the disc control was behaving like you suggested. i am not familiar how and ware coins should be reacting on this machine, but if you look at my second photo. i tested all these coins on two setting on the disc control. first on the "Ring Range Presetting" all coins were being picked up OK. then on the "Coin Range Presetting" not all the coins were being picked up. only the coins in the top row of the photo. does that seem about right do you think?

if you tested in air your tests are sure useless. you have to test in/at grund in real conditions and according RTM you have to tune GND BALANCE at first. in ALL-METAL mode.
while you do not even wish to mention that.