Reg, TDI Mod

[Frank-S]

Hi Reg
When you get time I like to get you to Mod my new SL TDI its No good to me as is.
It has poor dept,you mod a older TDI, On TDI forum compared to my new SL the older TDI
gets 4-1/2'' deeper on a nickel air test same 12'' DF coil than my new SL..
I E-mailed White detectors, Got no reply.
Frank s fjs5015@yahoo.com

 

[Reg]

Hi Frank,

We do mods on the SL but not for depth. Any mod done is to make the ground balancing easier and smoother and will add just a tiny bit of depth, but not like what you want.

My recommendation is to find someone who has a TDI or another SL and borrow a coil and check your depth with a different coil.

I think you mentioned you built a coil and it got better depth, so if that is the case, then your factory coil might be the culprit. That needs to be checked first.

What size factory coil do you have now?

Reg

 

[Frank-S]

Thanks,
Its not the coil.the coil is a stock 12'' DF coil. After testing the SL The SL that I have now
is the problem,The serial number ends letters BC. I don't recommend any one purchase a white
TDI SL that serial number ends with letters BC. I suspect the problem has something to do with
pin 4 and 5 on control box,and gain circuit.
My 7'' mono coil wont work connected to pin 4 and 5 on SL serial number ending With BC.
MY first SL the serial number ended with AOD1 My 7'' coil connected to pin 4 and 5 worked
good with good dept.It had better gain also.
Tell me how to increase Gain and lower us.I will do it as winter project, if your concerned what White
might do or say,I have e-mailed White they know that there is a problem with SL that ends with BC.
I got no reply.If some one ask me in future about White SL TDI what do you think I might say.
Frank Serra

 

[Frank-S]

Hi Reg.
I was looking over TDI forum, a post by Iytie 78 TDI with Reg Mod.
He was well pleased with your work. He said that he purchased a TDI that you
did a noise Mod and replaced a op-amp.
He also said he did a air test with a nickel the TDI detected it at 17'' with a
standard 12'' DP coil, DP coil is that a type 0 for DF coil.
17'' air test on US nickel is the right dept every one should get with one of
Eric top of line pi detectors with 12'' coil.
Reg How would you like to have a nice New White TDI SL pi still under
warranty with 12'' coil.
If you have a older TDI with your noise Mod, 12'' coil that will detect a nickel
air test.I will trade you my nice new White TDI SL pi still under warranty.
I don't care what kind of shape its in so long it works.
Frank-s

 

[Frank-S]

Reg. I made a mistake at bottom of my last post.
It should read (that will detect a nickel 17'' air test )
Frank-s

 

[Frank-S]

Hi Reg
Battery and chargger question.
My SL came with 3 batterys 2 nimh rechargeable and a 8 AA battery pack.
they all read about 9 volts when I first got the SL,I charged the Nimh batterys.
after setting a bout 2 weeks they both droped below 10volts.
Qusetion (1) is that normal for Nimh batterys.
I re-charged them both the battery charger turns off at 11.40 volts.
Question (2) is there a reason why White has the battery charger to turn off at 11.40 volts.
I can make a charger with higher voltage.
Question (3) if I go over 14 volts will the Nimh batterys explode.
Frank-s

 

[Reg]

Yes, there is a reason the voltage quits at 11.4v and that is because that is the maximum voltage for NiMH's. Trying to charge them more only ruins the battery or at least shortens its life.

Battery University says one should only charge NiMh's until they become warm, not hot. Anything above warm can cause shortening of the life of the battery and adds very little to the run time.

So, don't try to charge them greater than the 14v because the worst case is they will explode and the least is they will discharge excessive gas which can dramatically shorten the life of the battery.

Reg

 

[Frank-S]

Reg Thanks the charger that came with SL shuts off between 11 and 12 volts no problem there.
I put new battery's in the 8 AA battery pack it's just above 13 volts.
New air test with a nickel ( there is a increase of 2'' in depth at 13 volts )
As volts drops (depth drops off also)
What is the max voltage the SL will take before it will go dead.
Are the caps or circuits set at 35 volts or lower.
Frank.

 

[Reg]

The maximum voltage for the SL is 16V. Some of the large caps are rated at this voltage. So, keep the maximum voltage 16v or less.

Reg

 

[Frank-S]

Thanks Reg,
There is no Gain after about 3/4 turns of Gain pot.
In one of your post you talked about putting a wire across one cap to increase Gain.
Have you tried putting a 1k or 10k resister across the cap to see what it will do.
Will you tell me the number of the cap, I will have to increase Gain at a later date.

Reg did you ever live in Orlando FL, In 1964 a man made me a metal detector I forgot his
name he worked for Marton electronics he had a son that would be about your age.

Don't forget the number of cap to increase Gain I don't have a SL schematic.
Frank.

 

[Reg]

Frank,

The SL cap number is C42 and is located near U12. Shorting this cap helps with other problems and was not intended to be shorted to increase the gain. However, shorting it will cause an increase in gain, which can cause an increase in noise. NOTE!!!! the cap number on the TDI and TDI pro is different.

C42 can cause strange groans and possible loss of weak signals at least on some of the passes over a target. However, the recommendation to short it out was because it will eliminate a loud audio signal that will last a few seconds when the detector is first powered on when certain coils are used once the Aussie mods are done to the detector.

Reg

 

[Reg]

Frank,

I forgot to answer your question. No, I have never lived in Florida. I graduated high school in 1964 in Colorado.

Reg

 

[Frank-S]

Thanks Reg,
I need to increase Gain and lower Pulse delay.when you get time will you also
post what IC circuit controls resistance at Gain pot and Pulse pot also any resister
number that increases power and volume.
When I look for deep treasure or work a beach i don't much care about detector noise.

The man that made a detector for me in 1964 was very smart and ahead of time on detectors
the detector had a DD coil,it didn't like salt water but for back in 1964 it was a good detector.
in fresh water with the coil under water it would detect a target 8 or 10 feet,I never did go down
to see what it was.there was alligator's in the water back then.Knowing what I know now from
back research of 1715 plate fleet it might have come from it.a 1715 silver coin was found near
there. I have been detecting over 50 years,(a lot of may bees and what if.)
Frank.