Re: Velleman VTSSC40NU
The iron is "on sale" for C$79. Anyone? ... Or am I under the impression no one likes Velleman at all?
xtraelectronics
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Last Activity: 09-22-2010, 01:03 PM
Joined: 04-30-2009
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Velleman VTSSC40NU
Does anyone have any comments, opinions, yays/nays, etc?
[url]http://www.vellemanusa.com/us/enu/product/view/?id=522851[/url]
thanks, Danhttps://Does anyone have any comment...> thanks, DanDoes anyone have any comments, opinions, yays/nays, etc?
[url]http://www.vellemanusa.com/us/enu/product/view/?id=522851[/url]
thanks, Dan -
Re: Bad CCfL Tubes
Update:
Tackled one of the Benq's today (FP731). Initially, it would power up, display for a few seconds, (very bad pinkish/red tint to it) then shut down, green light still on. Upon disassembly, found 6 bulged caps on the inverter/ PSU. Replaced them, and resoldered the inverter section. Monitor now runs without shutdown. Still had pink/red tint. CCFL tubes were shot.
Had another dead monitor, (T705), so I exchanged the entire screen assembly, it now works perfectly! I will likely repair the PSU from the T705 for use later. I have several...Leave a comment:
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Bad CCfL Tubes
I just recently repaired an ACER1916W. The Caps and circuit all checked out ok. The monitor would be on for the typical 5 seconds, then black. I determined the CCFLs to be bad. Then I discovered the return wire on the top tube was loose. Poor soldering, so I resoldered the lead wire, and shrink tube, just like original. This corrected the problem. -Until everthing was put back together. Took it all apart again. Bottom tube was acting up. Could smell ozone when it was running. So I stripped off all the shrink tube, and resoldered all connections, along with new shrink tube. Put it all back together,... -
Re: Dell E172fpb
Also nobody mentioned that the C5707 is listed in the spec sheet as a "high speed switch". The reason the TIP41C's are running so hot is because they are not designed to operate this way. Look at the PDF spec sheets when deciding what transistors to use as replacements. C5707: [url]https://cdn.badcaps-static.com/pdfs/40284cffbe42543f4d0fb2964cb690e1.pdf[/url]
TIP41C: [url]https://cdn.badcaps-static.com/pdfs/300817c7c74cea7abcb2ea3d809d111d.pdf[/url]
NTE cross reference: http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$SearchRe: Dell...Leave a comment:
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Re: Oscilloscope CRT problem
Awesome! There should be a"tilt" control on the unit somewhere, that copmensates for the earths magnetic feild and other stay feilds in the vicinity. I had to adjust mine while it was on the bench, and again after it was back on its shelf.Leave a comment:
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Re: Oscilloscope CRT problem
Jeez I hope the schematic is wrong- the 100uF/50v cap across the +12/-12v is backwards! The IC is a common OP-Amp. (741). Looks like the corresponding resistor to the 2120 is R952, 51ohms. Check it and the zener. H.V. for the anode is off of junction of R950, and HR959.Leave a comment:
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Re: Oscilloscope CRT problem
The circuit boards are different in the 2120. The circuit itself is very similar. Test for voltage @ the IC, then check the device on the heatsink for voltage. It may trace back to a resistor elsewhere on the board that supplies this circuit. That bulging cap could have caused a failure upstream. Just my 2 cents.
DanLeave a comment:
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Re: Oscilloscope CRT problem
Unfortunatly I have reassembled my scope. Don't remember the tube #, but it was manufactured by Toshiba. Your scope is very different from mine. I would check the smaller value rsistors near the HV, and def. replace that bulging cap. A circuit tester, that electricians use contains a neon lamp. This is what I used to check fo high voltage @ the flyback. Just hold it close the the transformer, if there is high voltage, it will glow. Good luck. I'll check in again tomorrow to see if you made any progress.
DanLeave a comment:
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Re: Oscilloscope CRT problem
I might have overlooked the part about MV950. The 2120 has no such component, or a typical HV anode lead. All connections are made via the end socket on this tube. Hope I didn't cause confusio!Leave a comment:
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Re: Oscilloscope CRT problem
Ok, found R549 in the flyback cct open. It is a 47 ohm, 2 watt resistor. The scope now has HV and a trace. Tested the small caps in the area, they are marginal. Probably tolerated by the cct, but I think I will replace them anyway, just to be safe. There are a few others elseware in this scope that are def. bad. Hope this helps you
DanLeave a comment:
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Re: Oscilloscope CRT problem
I have almost the same scope. 2120. (no B) It's a bit older, but when I went to use it today, I was surprised to find the same sympton as you. No trace. I appears HV is missing. The scope acted "funny" the last time I used it, about a month ago. I will test some components, and keep you updated on this so maybe we can get to the bottom of this.
DanLeave a comment:
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Old School Proscan VCR
RCA Proscan PSVR60 Hi Fi VCR:
Well, It started out as an idler gear problem. Sent it back to the customer. Then it came back... The onscreen display would only show when there was a blue screen. The on screen counter did not show, either. Occasionally there was vertical roll, too. This customer has a lot of tapes, and reaaly wants this machine to work. (it's built like a tank, not like the throw aways of today) So, after carefull observation of the circuit board, it was noted that capacitors were leaking goop. An esr test found 24 bad caps! After carefull replacement of all 24, the machine... -
Re: Record for this shop!
Real sense of accomplishment for sure. Thats awsesome, Wizard! Make something useful out of what would normally go to the dump. I like to do that as much as possible.Leave a comment:
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Re: Samsung Syncmaster 740N
The values are clearly stated on the side of the capacitor. Be sure to get the same V rating (voltage, or a bit higher ok.) The uF value should be the same (I have used slightly more capacitance, but sometimes this will cause issues, so stick with the same value). There is also a temperature rating. ALWAYS use 105 dgreee caps in these and all modern electronics! Hope this helps.Leave a comment:
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Record for this shop!
We managed to save seven LCD's from the landfill today! Phew! Now I gotta order MORE CAPS!
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Re: Strange Symptom VP730b
Monitor has been running for 12 hrs, no problem. Yay! Fixed it!Leave a comment:
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Re: Strange Symptom VP730b
Ok just finished with this hairball. It seems corrupt data from the eeprom to the controller was the issue. I corrected this problem by simply dissconnecting the offending data line. I know it shouldn't work, but it does! he only issue now is the OSD is set for portrait mode so you must always pivot it back to landscape mode through the menu. Big deal. It is now usable!Leave a comment:
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Re: Strange Symptom VP730b
Update #2:
Installed all new, proper value caps today. Including two Lelons' that tested ok previously. I am able to get normal colour balance, but the picture has very poor contrast. Is there any way too boost that up, on a parts mod level, -the screens contrast is all the way up as is the brightness. (I subbed in a 5V on the inverter's brightness pin to no avail this is true even if I use another identical screen, so I doubt there is any problem with the ccfls.) Any ideas would be welcome.
thanks, DanLeave a comment:
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Re: Strange Symptom VP730b
Upate: Going into the menu for colour adjustment, I can't get any response to increase or decrease R,G,or B on the "User Setting" mode. Starting to sound more like a bad video proc. but I will replace the over valued caps back to their original values when the parts shipment comes in.Leave a comment:
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