?Strip Board? layout for the ?Bandido II U Max?.

Hello Eugene,
I have still not got the ? Discriminate ? circuit working,
I will list below what I have tried so far:-

Thoroughly double-checked the layout of the Veroboard around IC?s 5 & 7.

Measured the resistor values, changed both IC?s and C14.

The +ve and -ve rails are +5v and ?3.4v.

Checked the operation of the ?Disc pot? at the junction of R23 - R69. When I vary the pot from ?Min to Max? there is a ?10kHz sine wave? starting at (Min) ?2v p-p? and decreasing to Zero (Max), only when at Zero the Discrim stops working all together.
At IC5 pin7 I get a ?10 kHz 2v p-p? square wave all the time until the pot reaches ?Zero?, then I get an irregular square wave, mostly ?Hi? with short ?Lo? pulses of about ?4v p-p?.

I did check the junction C21 - R37, as you suggested I got  ?9mVall the time until the pot reached Zero, only then I got +16mv instead of  -25mV to +25mV.

I get the same fault on the ? Discrim ? whichever of my coils I use.
I have tried many other experiments, changing values around that part of the circuit all with varying effect, but no positive outcome. I can list them if you want.
I suspect IC7 is working correctly.
I notice on the ? Eldorado and the Golden Sabre ? circuits that the ?ve supply does not use the extra (T7) transistor stage, should I cut this out on my circuit to increase the ?ve voltage.

Any ideas Eugene.
Regards Mike.


Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,3620.msg39228.html#msg39228

		Quote:			Posted by Mike In2mud
	Hello Eugene, I have still not got the ? Discriminate ? circuit working, I will list below what I have tried so far:- Thoroughly double-checked the layout of the Veroboard around IC?s 5 & 7. Measured the resistor values, changed both IC?s and C14. The +ve and -ve rails are +5v and ?3.4v. Checked the operation of the ?Disc pot? at the junction of R23 - R69. When I vary the pot from ?Min to Max? there is a ?10kHz sine wave? starting at (Min) ?2v p-p? and decreasing to Zero (Max), only when at Zero the Discrim stops working all together. At IC5 pin7 I get a ?10 kHz 2v p-p? square wave all the time until the pot reaches ?Zero?, then I get an irregular square wave, mostly ?Hi? with short ?Lo? pulses of about ?4v p-p?. I did check the junction C21 - R37, as you suggested I got  ?9mVall the time until the pot reached Zero, only then I got +16mv instead of  -25mV to +25mV. I get the same fault on the ? Discrim ? whichever of my coils I use. I have tried many other experiments, changing values around that part of the circuit all with varying effect, but no positive outcome. I can list them if you want. I suspect IC7 is working correctly. I notice on the ? Eldorado and the Golden Sabre ? circuits that the ?ve supply does not use the extra (T7) transistor stage, should I cut this out on my circuit to increase the ?ve voltage. Any ideas Eugene. Regards Mike.

Hello Mike . Are you sure your search coil is correct ? If your search coil winding directions , polarity are not correct on the tx and rx . Then you never will get the proper discrimination range of +25 to -25 . I will check all the voltage readings you just posted , with all my information and get back to you . You are doing a good job and I think you are very close to solving this minor problem. T7 is not on my schematic !! What schematic are you using ? Let me know ASAP . Thank-You .
Regards.......Eugene

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,3620.msg39666.html#msg39666

Hello Mike . Make sure C10 is 22 pf capacitor !!!  Not 130 pf !!  Here is one more Bandido schematic , this version is from Gary and the [chemelec site] .
Regards.......Eugene
 

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,3620.msg39689.html#msg39689

hope these are right

Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,3620.msg39782.html#msg39782

		Quote:			Posted by davidbat40
	hi mike could you help with the right pots to get from farnell (order codes)just getting confused not includeing the 10 turn 50K one getting that from ebay 13 quid got a couple resistors toget all the caps the switches from maplins today or tomorrow then got until next friday to get it up and running (off to caravan for 5 weeks) have you got the ‘ Discriminate ’ circuit working yet

Hi David,
Here is the switch and pot information you wanted.
I didn't need to buy these all myself as I had a lot of them.
I think they should be ok.

From Farnell  you can get the pots :-

10K with switch Part No. 1637184
100K Threshold and Discriminate pot Part No. 9609377 (x2)
Instead of 470 ohm I used a 1K it worked better for the volume pot Part No.9353836

From Maplin you can get the switches and Stereo Jack :-

S1 switch is a SPST ON-ON (Auto / Normal) Part No. FH00A
S2 switch is a DPDT  ON-OFF-MOM (Disc, All Metal, Retune) Part No. FH06G
The Stereo Jack socket is Part No. BW79L

Hope this helps, sorry about the delay, it took a while to sort out.

All the best Mike.


Linkback:

You are not allowed to view links.
Please Register or Login

http://www.thunting.com/smf/index.php/topic,3620.msg39807.html#msg39807