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| FeelTech/FeelElec FY8300S Quick Tear Down |
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| edigi:
It's pretty clear based on your review that one has to start with disassembly (any hint there is welcome so that plastic is not broken) and go through your fix list. Even if nothing is obviously rattling a screw can be stuck already where it should not or it can fall out later on as well unexpectedly. There is no point taking risks here. Thank you for the fix list. |
| grizewald:
--- Quote from: edigi on January 21, 2020, 02:16:55 pm ---It's pretty clear based on your review that one has to start with disassembly (any hint there is welcome so that plastic is not broken) and go through your fix list. Even if nothing is obviously rattling a screw can be stuck already where it should not or it can fall out later on as well unexpectedly. There is no point taking risks here. Thank you for the fix list. --- End quote --- It's a pig of a thing to dismantle. The ends of the case snap on at the centre points both at the top and bottom and the sides. The plastic is fairly soft, so there's no risk of snapping anything, but you need four hands to release all four catches at the same time. In the photo below, I've circled the catches on the rear end panel. Obviously, each catch has a partner on the opposite side, so all you need is two larger prying tools for the long edges and two much thinner ones for the side catches. |
| grizewald:
Oh, and don't forget the screw which holds the upper and lower halves of the case together. The head of the screw is hidden under the label on the bottom of the case. |
| edigi:
Due to super fast shipping I've already received the device and have naturally disassembled. There is a neat trick for this and you need only 4 small coins (the smallest that you can find, in case of the front side only 2 can be used due to the handle). Gently push the middle of the case inwards and push the coins in (see picture). After this, push neighbor coins away from the device (or top/bottom coin + flat type of screwdriver in case of front). Only 1 minute is needed to completely disassembe the case (naturally without grizewald exploring where the catches are it would have been very hard). Nothing has fallen out but the fan is not rotating either... It has supply power so probably it's faulty (DoA). What I've noticed that the mains cable is very loose, almost falls out so a good fixing would require replacing the whole mains socket (if I knew where to buy one exactly the same size)... I can understand the safety concern of the forum members: the PE (Protective Earth) wire is probably failing to reach the minimum cross-section requirement even for enclosure (although I could not find what it is in EU) it's so thin. As I could not see how to make a final solution I've just used hot glue gun to stress relief the wires and prevent the fan or the screws falling out. Unfortunately the rear BNC connectors are way too short (as noticed already in some posts) and it's not easy to fix it since the case probably supposed to fix them in place. Without making the plastic thinner however there is a huge risk that either the BNC socket breaks or the cable plugged in breaks. So I had no other choice but to use my router (originally planned for wood...) as I don't have such large drill that would have been needed for this. Initially looked quite ugly, but when assembled it's barely noticeable. Next thing was the quick check of the functionality. I like how the SW developers have made an efficient use of the small screen space. It's really good (just like the documentation). Most signals don't have jitter (with a quick check I have the impression that log signals are an exception). This is very good at this price point. Frequency accuracy is however quite bad, even though it's still within specification (20ppm). After switching on it's roughly accurate, but warm-up means roughly 100Hz drift at 10 MHz. What's worse is that changing signal level or signal shape or anything that changes the heat generated creates a drift in the Hz range. For a signal generator this is too bad. One thing that would require SW fixing is the printout of the measured frequency. It can correctly measure GPSDO 1 Hz output duty cycle, however it prints only 1.0 Hz for frequency, where it could print 8 digits as well (like 1.0000001Hz) as the resolution is clearly there. I plan to replace the TCXO (?) with an OCXO (means separate PCB) if its startup current (0.55A @5V) fits into the budget of the 5V rail. The current TCXO (?) is 3.3V with square output. Unfortunately 2 of its pins (which have 3.3V) are close to a plastic socket so probably neither desolder station nor a hot air station is an option (Argh!.!.!). The pin that is close the closest chip is the output. I've checked the modulation with PMR device using harmonics (thus square as carrier) and it works nicely if radio is put close to the generator. If the developers are reading this some improvement ideas: - Safety first, use decent PE wire and cable isolation - Rear BNC socket is too short even with the supplied cable, it must be fixed - Better stability reference and possibility for external reference is a must - If the data is there use it for proper frequency resolution All in all value for the price is OK for me but it could be improved so it needs no fixing by the customer. It clearly cannot compete with the more expensive devices nor is it probably made for that target. |
| grizewald:
Nice trick with the coins, I'll give that a try next time I need to take mine apart. :-+ With mine, I put the cut wire back where it came from as I had the correct crimp pins for the connector on hand. I just crimped some 24AWG wire in a new pin and soldered the other end of the wire to the original cut ground wire. Then I took a proper sized and insulated cable and connected that (with a 10K resistor inline) to the PE pin on the socket with a proper spade lug and soldered the other end to the two ground pins on the underside of the power supply. With a 10K resistor, I measured about 30mV AC between the outside of the BNC sockets and earth. Like you, I noticed that the internal 10MHz timebase isn't anything to write home about, but then again, neither is the one in my HP 5334A - in fact, it's probably worse! If you want to wire it up so that you can feed it with a proper 10MHz reference from a GPSDO, just cut the legs on the clock chip. Then there's no risk of melting sockets and you're hardly going to use or need the internal reference again if you can connect a proper reference signal. |
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