1220XD help needed

[ash]

Hi everybody.
Has anyone ever trimmed in the coils on the C.Scope 1220XD please.
I have the 10" polo coil and am thinking of swapping it over for the 8". I've been told it will need trimming in.
Any help with this would be great

[ash]

Have just taken some pictures.
Does anyone know which is the coil trimmer please

[ivconic]

Hi everybody.
Has anyone ever trimmed in the coils on the C.Scope 1220XD please.
I have the 10" polo coil and am thinking of swapping it over for the 8". I've been told it will need trimming in.
Any help with this would be great

Is 8" coil made for 1220XD ? If it is than no need for any changes (trimming). If not than.... you must tell here for which model it is, originally?
BTW very nice photos. I envy you on 1220XD. Always liked good old Cscope. I do have brand new 770XD. Light, simple but very nice!

[ash]

Hi Ivconic.
Thanks for the reply.
My 1220XD has the 10" polo coil fitted. They were first made with the 8" solid coil,then brought them out fitted with the 10". They have made some new 1220XD's due to popular demand for a short period only. These they refitted with the 8" coil again.
I asked C.scope about buying the 8" coil to go on my machine,but they say it will need trimming in.
I also like C.scopes. Honest little machines.

Another thing i have noticed with my machine is,the threshold wavers about when audio/meter disc is selected.It is fairly stable in all the other modes. Has anyone else noticed this?

[ivconic]

Hi Ivconic.
Thanks for the reply.
My 1220XD has the 10" polo coil fitted. They were first made with the 8" solid coil,then brought them out fitted with the 10". They have made some new 1220XD's due to popular demand for a short period only. These they refitted with the 8" coil again.
I asked C.scope about buying the 8" coil to go on my machine,but they say it will need trimming in.
I also like C.scopes. Honest little machines.

Another thing i have noticed with my machine is,the threshold wavers about when audio/meter disc is selected.It is fairly stable in all the other modes. Has anyone else noticed this?

If they said it will need trimming in, than i guess it must be done. Although i do not understand why? Maybe is suggestable to fine readjust machine to specific coil, but i dont think it is obligatory. Without trimming, coil will still work with your detector. Trimming exactly on specific coil will improve performances just in small percentage. Both coils must be projected for same machine. I am not familliar with newest Cscope schematics, but i guess by "trimming" they mean fine readjustment of working frequency to achieve least possiblle residual voltage on specific coil. Cose , with frequency changes at the same time residual voltage at RX coil also changing. Both coils must be projected for 17kHz. At my 770XD there is also Isocoon coil and also the same frequency - 17kHz.
I just looked 1220XD video on youtube. Same audio and same behavior as on my 770XD. Except that 1220XD is more complex and for sure better machine. Also has more presets and better control over signal and over audio/visual indication.
I had 1220B in the past. Old but very good machine. Looking at 1220XD specification and video i am sure people from Cscope wanted to preserve good old spirit from 1220B and that's why they made new, modern version - XD. It is hard to beat good old nonmotion detector. So 1220XD is actually splendid machine. Keep it, you have excellent detector.

"..Another thing i have noticed with my machine is,the threshold wavers about when audio/meter disc is selected.It is fairly stable in all the other modes. Has anyone else noticed this..."

That looks like power supply / battery issue. Are you sure your batteries are good?

[erolunall]

Dear İvconik

My friend cloned Csope 770d but He can not find Coil info.

İf you could give coil paramaters he will try it.

I attached Pcb and I will sent other informations later.

Best Wishes
Erol

[ivconic]

Erol...i saw pcb there..hmmm..i dont think XD and D versions are the same machine. That version you posted looks much simplier than XD i have. Once i opened 770XD box, was curious and wnated to se what's inside. I was amazed with what i saw inside. It is not simple at all. Very complex machine but packed at very small space. Reminds mostly on photos we have here, which ASH posted already - photos of 1220XD, although 770XD is a bit smaller and simplier. I also recall some "770" model i saw in the past. It was very simple and poor performance detector. Maybe it was "D" version. Give me some time and i will take photos of my XD and post here also. Than you will see differences.
About coil... i busted up my inductance metter (4th time so far!!!) so right now i can not measure inductances. But i can measure resistances if any benefit from those. It is Isocoon 20cm coil, pretty ordinary Cscope coil. I wil prepare photos and available datas soon.

[headshed22]

CS1220XD

Hi all,
Not posted for a while.

I believe the CS1220XD supplied with the 10” polo coil was designated a ‘P’ suffix as in CS1220XDP.
As far as I am aware and from my own experiments with C-Scope machines, the trimmer for the coils is located inside the coil housing itself on a small circuit board. I think this is only used as a final nulling due to small tolerances due to the manufacturing process of the coils.
Ash, Your 8” coil should work perfectly well as long as it is from one of the models that operate on 17KHz (I think the R1 works at around 7KHz).
Here are some photographs of a C-Scope 8” solid coil from a CS660 that I recently opened up in order to experiment with and make some shielded double ‘D’ coils.
On the DD’s I did away with the whole board and just placed a 47nf poly capacitor across each coil. The oscillator being a Hartley type these set the frequency. Then I just null the coils in the normal way with an oscilloscope.
I also own a CS1220XD with 8” coil, a CS770XD, the CS660 mentioned above and a CS4ZX. All have been fitted with XLR sockets and plugs on the coils.
I find all the coils are inter-changeable (including my home made ones) on each machine.
Hope this is of help,
Regards,


Russ

[ash]

Many thanks for the great help everyone
Russ. I haven't got an 8" coil. Just the 10".
The signals seem less positive with the 10" coil than when i had my first 1220XD that had the 8" coil fitted.
Tell me please. Does your 1220 make a different threshold noise,when you select audio/meter mode over any of the other 3 modes.
When i select meter/audio mode,the threshold rises to a higher pitch.
Cant remember my first one doing that though.Mind. It has been a while since i had that machine.
Ivconic.I have followed your advice,and checked the batteries and the connections.I have also swapped batteries. All seems ok in this department. They are great little machines,yes. I agree with you. I plan to keep it for a long time yet.
The 1220XDP was the model that was fitted with the 10" polo coil.You are right Russ. As was the 2MXP and the 5MXP.
Tell me please. How do you find the DD coils you have made,work on these machines. They sound great.
I spoke to C.Scope about a new coil 8" for my machine,but they said i would have to send the machine to them to have the coil trimmed in etc. It might be worth then,tying to find a secondhand 8" coil and trying it on my machine.

[ivconic]

Erol and others,
here are some mesurements taken on Isocoon coil a while ago, if any help...
11 ohms / 1,9 mH
8 ohms / 1.9 mH

[headshed22]

CS1220XD

Like your 1220XD Ash, mine indeed also has a different threshold pitch when meter/audio discrimination mode is selected, usually a slight increase in pitch. Apart from the addition of the XLR type plugs and sockets mentioned for interchanging coils, it is unmodified and in 'stock' configuration. I would suggest that this slight change to the audio pitch is due to the audio discrimination being selected (variable tone rises for good targets & lowers for bad targets) I think some users labelled it 'bubble and squeak discrimination' due to the strange tones when the machine is used in this mode. (Its best feature I think).
Yes my DD coils work reasonably well on this and my other C.Scope machines, providing very similar depth capabilities but with the added advantages of much improved stability and ground cancelling.

As to your coil Ash, let me suggest that you 'reverse the phase' of your TX coil within the plug of the coil, that is to simply swap over the red and black connections inside the plug. Solder the RED lead to where the BLACK one is and then solder the BLACK lead to where the RED one is.
C.Scope appear to be not too fussy as to witch way around they connect these leads to the socket at the factory and then match the phase on the plug later when setting up. Maybe that is what they mean when they request the machine is sent back to them for trimming. (Clever marketing or what).
I have configured all my C.Scopes XLR sockets & plugs so that the coils all connect in the correct phase.
Other than this I can see no reason to 'trim' the stock coils as they all seem to be fairly accurately 'nulled' at the factory, probably on a reference oscillator as opposed to individual machines.

Ivconic,
Your coil measurements are virtually identical to my own.

wish I could explain better.

Russ.

[ash]

Many many thanks,Russ for the great reply

I see that the C.Scope 660 is hard wired to the mother board

Are the coil wires the same as the 1220XD etc,please.
If so,i would just need a coil plug.
I have had no luck in finding an secondhand 8" coil for the 1220 as yet. But been offered a fully working CS660 for £50-60.
I also, like the idea of an auto tune fitted to the 1220XD.It should be good.
The DD coils sound great. It is a shame that C.Scope have never made different coils for their machines. 10" x 5" DD. A round 11" DD and an 8 1/2" DD. As you say Russ. A better job for bad ground.
I have just tried my 1220XD against my young cousin's CS990B that also has the meter/audio mode. I forgot he had that machine
The threshold rises on both our machines when this mode is selceted and only this mode. The other modes,the threshold holds the same pitch in audio.

[headshed22]

You are welcome Ash,

A price of £50-60 is quite reasonable for a good CS660, I see them advertised regularly for around £75 to £85 privately and up to over £100 at some dealers.

As you say the coil on these machines is ‘hard wired’ but both the coil itself and the connections are indeed the same so they would be compatible.

The 660 can be a very reasonable machine too by the way so if you were to buy it you could maybe add a socket to the 660 and a plug on the 8” coil, then you would have two machines with interchangeable 8”/10” coils.

Is the plug on your coil a bayonet type or screw in? As I have a spare plug and socket that you would be welcome to from either my 1220 (bayonet) or CZ4ZX (screw) both have short lengths of cable still attached.
I will take a photo in a little while and post on this thread and if the same just let me know?

Regards,
Russ.

[headshed22]

plugs & socket pics

1st pic Bayonet type (should be this one) and screw type, let me know Ash?

[ash]

Many thanks Russ,for the very kind offer of the coil plug fittings. I am more than happy to pay you for them though.There is also the cost of the postage to consider.
I've never tried the 660 in the fields,but i did have a go with one in a car park,where a chap had just bought one. It rejected a spanner and other iron objects with ease,whilst still giving good signals on non ferrous. For such a basic machine,i was impressed.
Could be just the machine to use in badly infested iron sites.
It would be interesting to try these machines with interchangeable coils as well. More so,the 660.
I have included a few pictures of my coil plug etc. Hope they come out ok.
Regards
Ash