RELIC HAWK

[Max]

RH Pro V.99.8 II special

Fred.

Hi,
nice PCB!

I like it...

about switch... I don't know must recheck everything again... I'm surprised too that switching a 22K resistor there I have no visible effect...

Looking at some PCB here... I saw one capacitor with very large dimensions... so my thought are also about wich kind of capacitor and why it's there.

I've used a common 1uF stuff... poly kind, a small one.

Unfortunately I think there could be errors in the schematic... in such a complex schematic even a wrong sign can lead to failure.

Kind regards,
Max

[Max]

Hi Fred,
solved the problem at motion-no-motions stuff: was the switch

I swapped a good one... (3 positions single) with a bad one, same colour etc... that was keeping always the 22K connected!

Was my BS !

Now works, sure it's just for all-metal, cause disc is always motion by design.

Kind regards,
Max

[ivconic]

As i recall it was 1uF/160V...WIMA

[Max]

As i recall it was 1uF/160V...WIMA

Hi,
1u 160 is small cap... and good for no-motion stuff...
do you remember if it was at TX the big one?

I think maybe the big cap is in parallel with coil... cause could give better stability.

Kind regards,
Max

[ivconic]

No, that one is designated as C215. Other one is smaller as you can see on photo.

[Max]

No, that one is designated as C215. Other one is smaller as you can see on photo.

Hi,
so the big one it at no-motion...and 1uF 160V WIMA... maybe cause have less leaks and that's good to mantain stored voltage there for longer time? Probably...

I'm using a common poly and works good now that switch stuff is fixed.

I still have troubles with disc instead, poor performance and not reliable, probably there's a mistake in schematic along disc stuff.

Kind regards,
Max

[ivconic]

Dont know...maybe you should compare all three schematics. Although first two are mostly faked and inaccurate, there is chance that you can spot something and find mistake. I havent started building this yet. Sorry i cant contibute much, for now...
Regards!

P.S.
Original RH pcb is mounted in massive Al enclosure. Front and rear panels are "coated" with Al foil also. All togather (including enclosure) connected to gnd. This tells us something...?
Max try to shield your pcb in simillar manner and than check its behavior. It seems some stages are more than sensitive and easilly saturate..

[Fred]

Dont know...maybe you should compare all three schematics. Although first two are mostly faked and inaccurate, there is chance that you can spot something and find mistake. I havent started building this yet. Sorry i cant contibute much, for now...
Regards!

P.S.
Original RH pcb is mounted in massive Al enclosure. Front and rear panels are "coated" with Al foil also. All togather (including enclosure) connected to gnd. This tells us something...?
Max try to shield your pcb in simillar manner and than check its behavior. It seems some stages are more than sensitive and easilly saturate..

Hi Ivconic,
That is interesting,
Is this RH you have working ? if so , maybe you could take oscilloscope measures at some strategic points?
regards,
Fred.

[Max]

Dont know...maybe you should compare all three schematics. Although first two are mostly faked and inaccurate, there is chance that you can spot something and find mistake. I havent started building this yet. Sorry i cant contibute much, for now...
Regards!

P.S.
Original RH pcb is mounted in massive Al enclosure. Front and rear panels are "coated" with Al foil also. All togather (including enclosure) connected to gnd. This tells us something...?
Max try to shield your pcb in simillar manner and than check its behavior. It seems some stages are more than sensitive and easilly saturate..

Hi,
all this seems tell us, do not use it without shield!
Yes, it's really sensitive to noise... cause of its so hi amplification... many stages easy saturate with also low amount of noise... I found that even a long track on PCB make it acts like crazy...

So better would be provinding a bit of EMI shielding if possible.

Kind regards,
Max

[Fred]

Hi,
Here is a picture of the PCB with cleared holes, i could ave done on PCB but it works that way too .
Maybe usefull if anyone want to build it.
Regards,
Fred.

[KingJL]

I still have troubles with disc instead, poor performance and not reliable, probably there's a mistake in schematic along disc stuff.

Max,
I am sure you already know this... but, the RH bandpass (-6db) in DISC mode is 3Hz to 19Hz centered at 7.5Hz. Whereas the band pass in all metal is 0 to 8Hz. In disc mode, if you do not keep the motion of the target at a fair rate the sensitivity will be poor.

Regards,
J. L. King

[zzy]

Hi,
Here is a picture of the PCB with cleared holes, i could ave done on PCB but it works that way too .
Maybe usefull if anyone want to build it.
Regards,
Fred.

Hi Fred,
Very nice pcb you had made.How do you make it?

[Max]

a mistake on schematic ?

Hi,
I think there's a mistake in schematic at U8... where trimpot connects to the 6K8 via 10megaohm resistor...

Why ? I tested the effect of turning the trimpot! In the schematic way... the effect is zero: I mean I would expect something change at output of U8 and so see something (good or bad, no matter) about audio and detection... but nothing. Trimpot seems serves nothing like connected in schematic.

Then I made a measure at pin5 of U7 when in all-metal and detector works with average results... 26cm for 1eur on air: the measure give about GND level (fluctuating a bit) at pin5 in all-metal.

Then I measured again in disc mode... and wow... I read about 85-90mV there... I mean it seems not even close to 0volts... and considering gain of U7b... well I was really astonished of that voltage there...

There's enough to saturate output stage there... without any signal...

Then I was thinking why that way of connecting the trimpot... and which kind of threshold one can achieve that way... change very few turning it when connected as in schematic, not enough to make output of U8 stay near GND level.

So, had the brilliant idea that's probably a mistake in connections and the 10megaohm must be (maybe) at pin6 of U8 to compensate stuff... et voillà... this way I can compensate to gnd as I want turning the trimpot...

I told you there must be something wrong... now I get stuff in disc mode about like in all-metal... maybe just 5% reduction of depth once tuned.

Do you think also the error was there ? Make sense to you ?

Now big troubles are about disc itself, not about detection range but about ignoring iron stuff... still doesn't work. But much probably this is pure phase issue only.

I think I will stop smoke my dang cigar for now... too much fog...

Kind regards,
Max

[Max]

Max,
I am sure you already know this... but, the RH bandpass (-6db) in DISC mode is 3Hz to 19Hz centered at 7.5Hz. Whereas the band pass in all metal is 0 to 8Hz. In disc mode, if you do not keep the motion of the target at a fair rate the sensitivity will be poor.

Regards,
J. L. King

Hi,
you're right, but I think there was a mistake... read my post about.

Actually I get some lower detection in disc mode, probably due to the bandpass effect...

before I correct the "mistake" detection in disc mode was just 1/3 of that I have for all-metal... now difference is maximum of 5%.

Kind regards,
Max

[KingJL]

.... but I think there was a mistake... read my post about.

I think you are 100 % correct about the probable mistake. The trimmer/10Meg connection makes no sense as currently drawn.

Regards,
J. L. King