NRG PLL Pro III - will not lock

[radium98]

LeeCavanagh with few skills yes

[LeeCavanagh]

LeeCavanagh with few skills yes

Thanks. Both
‘

[BriansBrain]

I'm still waiting for the CMOS HCF4060

Regarding the Crystal
The NRG pdf says it's AEL 6.4000 MHz Crystal

The Enigma Component shop in the UK have Crystal 6.4000MHz HC49 low profile
But I can't find info about it if it's a 20pf or 30pf

Any help would be... well......... Helpfulll

.

[LeeCavanagh]

It’s not showing a steady reading,

If I put my finger on the vco the red unlock light does come on then goes off when I release, so the pll unlock indication are doing something but it’s still not locked on freq even when it’s solid green , once it’s warmed up it appear to be steady ish but it’s difficult to get rid of the .05 which the pll should be doing, I’ve replace ic1 and ic4 and I have a couple of SN74 but not sure if they are a match for any of the existing. Ic4 gets hot (but that could be normal).

I have a spare xtal so will give that a try later

[BriansBrain]

I have a spare xtal so will give that a try later

Hi
Is your spare xtal a Real Genuine AEL 6.4000 MHz Crystal
If so where did you get it from ?

.

[jvok]

I'm still waiting for the CMOS HCF4060

Regarding the Crystal
The NRG pdf says it's AEL 6.4000 MHz Crystal

The Enigma Component shop in the UK have Crystal 6.4000MHz HC49 low profile
But I can't find info about it if it's a 20pf or 30pf

Any help would be... well......... Helpfulll

Looks like AEL was bought out by Abracon and don't make 6.4mhz parts any more.

You could try contacting Enigma and see if they'll give you specs on the xtal. But my advice would be to fit the mouser part (or search same part number on other distributors to see if you can buy locally) then change C60 to 18pf to suit the lower load capacitance.

Of course all this is assuming the xtals the failed part. Maybe worth ruling out the other cheaper parts first before you worry about the xtal too much.

[jvok]

It’s not showing a steady reading,

If I put my finger on the vco the red unlock light does come on then goes off when I release, so the pll unlock indication are doing something but it’s still not locked on freq even when it’s solid green , once it’s warmed up it appear to be steady ish but it’s difficult to get rid of the .05 which the pll should be doing, I’ve replace ic1 and ic4 and I have a couple of SN74 but not sure if they are a match for any of the existing. Ic4 gets hot (but that could be normal).

I have a spare xtal so will give that a try later

What type of counter do you have? Is it a type with a probe like a scope or a non contact one you just hold near the circuit?

[tvtv]

It’s not showing a steady reading,

If I put my finger on the vco the red unlock light does come on then goes off when I release, so the pll unlock indication are doing something but it’s still not locked on freq even when it’s solid green , once it’s warmed up it appear to be steady ish but it’s difficult to get rid of the .05 which the pll should be doing, I’ve replace ic1 and ic4 and I have a couple of SN74 but not sure if they are a match for any of the existing. Ic4 gets hot (but that could be normal).

I have a spare xtal so will give that a try later

What type of counter do you have? Is it a type with a probe like a scope or a non contact one you just hold near the circuit?

It’s a cheap one but I have used it previously to confirm the out put of pa’s, it just takes a 9v battery, has an sma connector of which I have a probe coming from the center…. I will try again later

[tvtv]

I have a spare xtal so will give that a try later

Hi
Is your spare xtal a Real Genuine AEL 6.4000 MHz Crystal
If so where did you get it from ?

.

It was from Mouser , it’s the one mentioned above

[tvtv]

This uk shop also has 6.4mhz crystals (I only found them in a search on google just now, never used them but maybe others here have)
https://symkrilag.uk/shop/crystalsosci ... -hc-49-18/
30pf load

[LeeCavanagh]

Swapped out the crystal, it didn’t make any difference.

However I have noticed a resistor is burnt and it’s damn hot , looks like whoever built it originally put a low rated 33r next to the voltage regulator, typical I don’t have any to hand so I’ve ordered some better ones with 1% tolerance too. That should sort out the wrong voltage on pin 16 ic1 hopefully

It was still getting hot but no longer giving accurate resistance

[BriansBrain]

You could try contacting Enigma and see if they'll give you specs on the xtal.

OK.... I have contacted Nick at Enigma - waiting for a reply

Maybe worth ruling out the other cheaper parts first before you worry about the xtal too much.

True...... Firstly I will be replacing IC1 (when it arrives)
The board is prepared I've already removed the old one

.

[BriansBrain]

This uk shop also has 6.4mhz crystals (I only found them in a search on google just now, never used them but maybe others here have)
https://symkrilag.uk/shop/crystalsosci ... -hc-49-18/
30pf load

Symkrilag.UK - 6.400MHz Crystal.JPG

Fantastic, I will wait to see if replacing IC1 works first

.

[BriansBrain]

True...... Firstly I will be replacing IC1 (when it arrives)
The board is prepared I've already removed the old one

Well... the IC arrived today

Put it in and... the same = No Lock
13.8v, = OK
5v = OK
IC1 pin 16 = 7.339V
Next check IC1 pin 15 on a scope for 6.25khz square wave = NO



Waiting for a Crystal now

[BriansBrain]

OK so next suspect the Crystal

Took the old one out for the Simple Crystal test

Crystal Test.JPG

Tested OK @ 6.39879 MHz

But only a small increase in Voltage at the Resonant Frequency

Generator output 3.30V P-P measured on Scope.
Measurement with the Crystal in series 3.66V P-P on Scope.

Should it not give a much higher Voltage at the Resonant Frequency ?

.

[BriansBrain]

On the Siglent
Start 6.3MHz
Stop 6.5MHz

PNG1.jpg

The first Time I played with a Crystal, is it OK or ?

[radium98]

i dont understand ,or imagine Brian who repair big amplifier and make own software and install solar , could not solve such easy task , there are few components around 4060 it is so easy to spot the problem ,you have such instruments and this oscillator quartz could not be solved , i could not imagine that , 2 caps and 1 resistor and the ic .

[BriansBrain]

i dont understand ,or imagine Brian who repair big amplifier and make own software and install solar , could not solve such easy task , there are few components around 4060 it is so easy to spot the problem ,you have such instruments and this oscillator quartz could not be solved , i could not imagine that , 2 caps and 1 resistor and the ic .

I know...........it's also doing my head in

The IC is new and fitted perfectly.
The Crystal measures OK as far as I can see.
The resister measures 100K.
There are only the 2 caps to go

[BriansBrain]

The IC is new and fitted perfectly.
I have tested the Crystal and it seems OK

I removed and replaced NEW...
R48 100K
C61 100pF
C60 33pF (replaced with a 30pF)
Re-Installed the Crystal Cleaned and checked the Print so everything = Perfect

Capture.JPG

Now for Test ...
IC1 pin 15 on a scope = 6.25khz Square Wave YES
Carefully twiddled VC1 - and Bingo - it now Locks

Thanks to everybody for the help

[radium98]

You see I told you that from the first time but you ignored me .Anyway congratulation .I wish my problem in comp limiter will be solved too