I bought one and waiting for it to arrive. I'm restoring an old Lafayette Comstat 25 CB from the 60's, an want to check the crystals. It is good to see and here people are having good luck with this product. Thank you for the build and review on this item.
One thing to remember when testing crystals is load capacitance and inductance will change the oscillation frequency. People frequently ask me if they can send me crystals for a old tube type radio so I can test them to see if they are in spec. Unfornately I have to say no. I have a Sencore frequency counter with built in crystal tester but what the crystal oscillates at in the counter is going to be different from what it will be in the radio. Still a nice tester for testing to see if the crystal is still good and see if it's close to the listed frequency. One suggestion would be to add a transparent red window over the display. It would make it a lot easier to read. Thanks for sharing.
Very important point to tell and especially for crystals in tube circuits. All new crystals are very close together in spec's but not in the early days. Thanks for comment Mike!
Hi, it's been four years since the video was released, but it won't work for me, the readability of the display has been reduced by not removing the protective film, it creates annoying reflections and the camera doesn't give it. Using a red filter will improve readability, even for the eye 👍
Peter: Thanks for the good video about the crystal tester. I just completed one with a couple of modifications. I moved the crystal socket up to be even with the top cover and added an HC-6/u crystal holder to the front side for all the older crystals.
I was surprised how accurate this thing was on the 10.000 MHz crystal.. cool! I didn't even really need one but since it looked like an interesting kit, I purchased it off ebay (cheap). I wonder if one could extend that three pin socket for the crystals up higher to be flush with the top of the case. That would really help.
You see Peter if you put the display in up side down, dots at the top, when you switch it on all the numbers would fall out of the bottom of the display hi hi, I have built one actually nice for the crystals to see if they work, I used a dremmel to make the slot bigger. Paul
Just built mine. The values for C2,C3 should be 47p or and C4,C5 22p. I was able to measure a small pile of old used crystals and the frequencies are all close to the fundamental value. FYI this circuit will not measure all crystals it just depends on the crystal. This was a interesting build for the price.
I've had a very similar version (but the one on a red PCB) for some time. It cost about £5 and actually is a pretty good frequency counter as well as crystal tester
the frequency counter of this project was originally developed by Wolfgang Büscher, DL4YHF. Trust me, it works PERFECTLY. The Chinese just added a simple oscillator to test the crystals... you can read about this on his website.
I bought a kit of these however when mounting did not work when analyzing the circuit I noticed that I send the same with the KYX3561BS which is a common anode display, being what works in this circuit without any change is the KYX3561AS common cathode, after searching the display I noticed that the project and the DL4YHF, I ended up changing the Pic File to Counter 3 , also changing the position of the diodes d2, d3, d4 and in place of U3 a BC557 and the diode d5 must have katodo connected in the emitter of the transistor U3 and the Anode connected to vcc .....
You are absolutely right Dino. It is a nice little lab helper and will give you additionally a idea on the crystal frequency even it is not 100% accurate.. Thanks for stepping in 73
Mine came from aliexpress with bad PIC. Showed only single zero in all modes. Internal quartz check circuit was ok. I rechecked schematics and PCB and everything was fine. Tried to re-flash it - no luck. Wasn't able to erase it with ExtraPIC, PICKit 3 and Triton - it seems that PIC had some memory issues. Replaced it - and now everything works fine. Search for TheHWcave/PIC-freq.counter-modification GIThub repo for firmware.
Nice job showing us the kit. I would of liked for you to test the counter too. Ya I know that it is not a high end counter but it would be nice to compare it with a good counter. just a note, some xtals require some parallel capacitance to bring it on freq. So the two that showed off freq might need a external cap. I think I am going to buy a kit... TU
I have the same unit and another different "red" unit with a trimmer capacitor. Both units will NOT read above 20 MHz properly. example, 37.600 MHz displays 15.53xx. Other 37, 38 45 MHz crystals show similar results. They 'divide' by 3-ish and that's what they display. Anyone know the fix?
I haven't put mine together yet, but instead of the 7550-1 5V regulator, they sent me a 7550A-1 which is a N-ch JFET according to my Peak Atlas DCA 75 Pro analyzer. That might have something to do with it not working right. The schematic shows a voltage regulator with grn, in & out, but of course, a JFET has gate, source, and drain. It's also a strange JFET that has the gate at Pin 1. I can only find data sheets that show the gate at Pin 3.They also sent me 2 102 caps and 3 22p caps.
Great build and a nice little tester Peter. The price is right also. Thanks for sharing this. Should help folks on a budget. Would be interesting to see the counter function. Also watch where your thumb ends up. Ouch!!!
i seen you had uploaded a video on the crystal tester so i made a quick video for you to see what my findings were all the best Barry G0SCI ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-5b3nBhZnT0s.html
So this device measure the frequency from the quartz oscillator; why do you not trust it as a frequency meter for external signals as you said in the beginning of the video? If it count the frequency well does it matter if the input signal that it counts came from its crystal oscillator or another source?
Good presentation! You covered all the points I teach my grandson about assembly, except for one. That is to cover the board with one hand while you clip the leads with the other - just to control where the cutoff piece goes. He wears safety glasses anyway, but safer is better. Now I'm off to order the kit!
my friend has to send the instruction manual so I can mount my frequency meter because my aki my mother threw it out unintentionally thank you if you can help me
I wonder if that crystal testing functionality can be integrated into those 3 wire component testers that are all the rage on ebay for quite some time now.
I have the lesser expensive red pcb model & it's good but does not appear to have the freq range of this yellow board model. Thanks again TRX Bench for your wonderful videos.
just soldered it together, not sure how high it will go, my 50MHz crystal reads 16,8MHz, but it could be that the crystal is trippeled in the equpment were it came out, measuring 1MHz big housing crystal failed not sure why
Got my kit in and built it. When I apply power, the display shows 8888(blank). 3 eights and the last digit blank. I double checked all components and everything looks in the correct position and the no solder bridges. I wonder if the PIC is acting up. Just thought I would send you what my experience is so far. I am not sure what to do at this point but will try to see if I can find out the problem. I also had the screws for the case were too short so I will have to go to hardware tore to get correct size. 73, ad0am
That was good Peter different but good, you didn't press the button. What was the button, I was hoping you would press the button. Well anyways you just can't help it, your troubleshooting picture's now (LOL). I like using blue tack when populating boards, I put some in the middle of the board. Stick it to the bench then solder, as the component gets taller add a little more. It just helps to keep the board from moving and the component well seated. Have a nice day and Cheers ... 73 Out
Thanks for watching Tom! Of course I pressed the bottom. It switches in a kind of programming mode with different commands by stepping through. May be a boot loader function or so? Nothing mentioned in the manual.. Cheers
Aaah, another Sunday with Peter....Makes for a good day no matter what he's up to. Thanks Peter. Used to be when we owned an FM broadcast station that our crystals lived in a heated oven, supposedly to assure correct frequency.
Crystals are sensitive to temperature so running them at a controlled, constant temperature will keep them closest to the oscillator's designed frequency (OCX)
Putting the jumpers on the lower two pins will invoke the frequency counter mode and the terminals ... ground and signal .... are for the input signal to be measured/counted.
Oh yeah, I never build a kit or replace a component without checking it first. I used one of my own 5V fixed positive regulators and it's working great.I informed them about the problem. They offered to give me a refund of a few dollars but I told them not to worry about it. I'm sure I'll need the JFET sooner or later. I just let them know so they could be careful and not get a bad name from newbies and people that don't check components before they start soldering.
Yeah that is the 40+ years old discussion and still going on LOL. It has been told that you should cut leads before you solder them because the cutting could cause micro cracks which can make gear fail. For production that is certainly right but for rework I have never done it and I don't do it in the future. I have never experienced any problem with electronic gear doing it my way..What is your opinion on that?
Hi Peter built 2 of these and both give me the exact same fault just displays 8.8.8.8., double checked soldering and components, my display are both KYX3561BS ? any idea's i have a crappy circuit diagram ? 73 James
