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| Need a scope, Is vertical sensitivity important? |
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| deezdrama:
Ive been doing maintenance on dozens of expensive 15kHz crt tv's and pro monitors... Usually just a deflection circuit capacitor replacement brings things back to life after I test the caps for bad esr and replacing the suspect capacitors but am working on a sony pvm 20m2u that worked fine after a recap for about 30 minutes before another component went out and caused image unstableness and a loss of vertical sync. I reflowed the board, tested all caps again, checked that no resistors had failed open, checked diodes for voltage drop, replaced sync ic chip.... On and on.... I need a scope! It will be my first scope and will learn to use a scope on it. I dont want to have to spend $500+ if I dont have to. Ive seen alot of great reviews and alot of bad reviews on the Fnirsi-1014d which is around $150. https://www.walmart.com/ip/FNIRSI-1014D-7-inch-Signal-Generator-LCD-2-In-1-Dual-Channel-Input-Desktop-Oscilloscope/278754013?athcpid=278754013&athpgid=AthenaItempage&athcgid=null&athznid=utic&athieid=v0&athstid=CS020&athguid=Vk0iS9SzrNvZuBUN1E4nL1W3L9eGhrc9bGZ_&athancid=null&athena=true&athbdg=L1600 My biggest concern with it is with Vertical sensitivity only going down to 50 mV/div. Ive read this makes reading signals under 1v spotty at best. Im not even sure what specs I need in a scope. Most of the high voltages in a crt are easy to troubleshoot without a scope..... Its all the rgb and sync level driven IC's on the board that I need to troubleshoot and alot of those are under 1Vpp so I dont want to end up with a scope thats not good for troubleshooting these areas on the chassis boards I work on. I really just need a scope to probe the monitors chassis boards IC's to compare results against the service manual. Theres been some buzz on this little battery powered 200kHz scope as being a good buy for checking rgb and sync levels but again, not sure of its vertical sensitivity range or if it would suffice for basic testing against the service manual of these crt monitors? Mini Digital Oscilloscope, Leolov Oscilloscope Kit Support AUTO, PWM, One-Button Reset Button, Firmware Update, 2.5MS/s Sampling Rate, 200KHz Bandwidth, 2.4 Inch LCD Display with 10X Probe https://a.co/d/5x428Aw Id love a rigol but the highest I could swing right now is around $300 on something like this siglent Siglent Technologies SDS1202X-E 200 mhz Digital Oscilloscope 2 Channels, Grey https://a.co/d/iJGNm8S Its claims .5mv vertical sensitivity Im not even sure if these vertical sensitivity specs are important for what I need. I just need a cheap scope to learn on and to test/troubleshoot these old crt monitors and compare waveforms vs the ones posted in the service manual to pinpoint problem circuits in the chassis boards. Any help is appreciated! |
| Pilatus:
For the kind of work you do, I would think that a good analog scope would fit your present requirments and give you a better understanding of what a scope can offer. Used ones can be had on ebay for $100 or so. In general vertical sensitivity and bandwidth are important parameters, however you need to define what you will be using it for. For CRT type of work, audio etc, 5 mV should be fine. Others will definitely be chiming in here soon and likely offer you more refined feedback. |
| pcprogrammer:
There is the Hantek DSO2C10 which is more sensitive then the FNIRSI-1014D, but is does have several bugs in the software. It is in similar price range though, and most of the C units are shipped with the AWG components installed. A simple upgrade can be done to turn it into a DSO2D15. The FNIRSI only does 200MSa/s per channel, where the Hantek can do 1 channel on 1GSa/s or 2 channels on 500MSa/s. It also has way more sample memory. The FNIRSI has only ~30MHz bandwidth where the Hantek has 150MHz. Both units have been dissected thoroughly here on the forum. But to be honest the best advice would be to squeeze the budget a bit more and try to reach for either the cheapest Rigol or Siglent scope. You will get something better with them than the FNIRSI or Hantek, or any of these other cheap brands or low sample rate, small screen toys. |
| bdunham7:
In general, to avoid frustration and wasted money, just avoid junk. I'll leave it to others to define 'junk', but I'm pretty sure FNIRSI and Yeapook fit the description. When you use a scope you typically want to use 10X and even 100X probes to avoid circuit loading as well as looking at high voltages. So vertical sensitivity and low noise are important even if you aren't looking at very small signals. 5mV/div would be the very worst that I could accept, 2mV/div was a sort of common spec for analog CROs and 0.5mV/div is what a decent modern DSO will give you. |
| deezdrama:
Thanks guys! Ill skip the cheapies, I just watched Kerry Wongs teardown and yeah... Ill avoid those. Any thoughts on this siglent? Siglent Technologies SDS1202X-E 200 mhz Digital Oscilloscope 2 Channels, Grey https://a.co/d/6KV85BK Also....Im not opposed to looking for an older rigol or siglent model used on ebay unless theres concerns about buying used, any particularly decent older models to look for that might fall in the sub $300 used range? Thanks for the help...much appreciated! |
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