Test Equipment Repair - Archived
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QUESTION NO. P60603-1: I need the type of transistor 2SC1412 and its replacement. It is of an oscilloscope IWATSU and TO-39 encapsulation.
The replacement for the 2SC1412 is a NTE194 Silicon NPN transistor audio power amplifier. Reference this website when crossing semiconductors: http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm
QUESTION NO. P31303-6: BK Precision 1564 Oscilliscope only comes on when I heat 2SA 1210 and 2SC2912 with the hairdryer although all four transistors (and other parts) checks ok. I would like to replace them just to eliminate the cause. BK said parts are NLA. What is causing this problem and how do I obtain these transistors or equivalents?
Your transistors are still available from multiple suppliers (try a search on Google), BK just does not stock them.
QUESTION NO. P21303-1: Philips PM 3226 oscilloscope. On the panel there is an output "probe adjust". No signal comes out. What kind of signal should come out? The signal is synchronized with the time base?
The normal expected signal would be a square wave the usual amplitude set at 1 volt. With this you can adjust the capacitance of your probe with the little trimmer at its end for a crisp square. Also by knowing the amplitude you use this as your reference when measuring peak to peak signals.
QUESTION NO. P41202-10: Huntron "B.C.P" 2000, DSI 700. Where can I get the software for interface with PC and user manual?
Check Huntron's web site http//www.huntron.com/ Software is available for download and you can contact them about the availability of the manual.
QUESTION NO. P1212-1: I need a source for an Matsushita 150DEB31 CRT for a Hungchang 3502 oscilloscope.
Matsushita is Panasonic's parent company. Call any authorized Panasonic parts distributor with the tube # and they should be able to order it for you.
QUESTION NO. P724-2: A guy wants to sell me a B&K rejuvenator 490B. I see lots of used monitors on a daily basis in our shop. Could this device be easily used to crispen up monitors?
The B&K range of CRT rejuvenators are aimed at the professional market and represent one of the best solutions for 'Flashing' low emmision tubes and clearing intermittent internal shorts. However, its biggest drawback is the longevity of the performance of the boosted CRT. Generally a tube with 'Poor' performance benefits with extended useful life, unfortunately the lower the performance prior to boosting equates to an proportionally shorter life usually as a result of cathode depletion. In my experience, the period of extended life varies from 6 months to a year and in some cases significantly less. The B&K would certainly be worth investing in if you only wanted to provide thinking time for existing customers.
QUESTION NO. P122-7: I feel it is finally time to invest in an Oscilloscope. Can someone tell me what bandwidth capacity would be most useful for the following types of repairs Computers, TV, VCR, DVD, CD, and Stereo? I am on a budget, and do not want to buy a scope that will be too small, or too large for my foreseeable uses. Would 20Mhz do what I need or should I get 100Mhz, or 200Mhz?
You'll need a high frequency oscilloscope to service the digital circuitry in the equipment that you're working on. A 100 MHz, dual trace, dual time base oscilloscope is the best choice for a limited budget. It is sufficient to not be too outdated in the near future, and adequate for servicing the products on your list. Bandwidths much lower than 100 MHz will cause the `scope to miss quick rise times, smooth out the ringing on square waves, and will cause rounding of the square corners of even low-frequency digital signals.
QUESTION NO. P1115-4: I am looking for a supplier of hardware for Tektronix 2235 scope. The hardware I am particularly seeking are the knobs for the vertical volts/div controls with the clear etched plastic attached with the graduations of 1-2-5 etc.
As a practical matter, broken oscilloscopes are sold fairly often on Ebay for their parts, and this may be the easiest/cheapest means of obtaining the parts you require. For the parts you want, other members of the Tek 2200 series (2213, 2215, etc) may be similar enough to a 2235, and may be more available, or cheaper at auction.
Parts for older Tektronix scopes can be had from Dean Kidd (503) 625-7363 in Sherwood Oregon. An EX-Tektronix employee, he keeps a large stock of obsolete parts. Prices not too bad.
QUESTION NO. P522-9: I am looking for a user/instruction manual for an out-of-production Tecktronix T922 'scope. Tektronix no longer carry the manual. Are there any other places to try? Also, are there any places that supply used parts for these 'scopes?
Ebay auctions (www.ebay.com) are a good source for old manuals. In fact, RIGHT NOW, there is an auction for your T922 manual (auction# 337486432), ending on 5/27/00. A website for purchasing old Tek (and other) manuals, including T922, is W7FG Vintage Manuals (www.w7fg.com).
QUESTION NO. P320-5: What is the proper way of testing transistors on a curve tracer?
Speaking in general, a curve tracer shows the input-output characteristics of a semiconductor. With regard to repair, a semiconductor that is not totally shorted or open, may still be inadequate, if its parameters (gain, etc) have altered so that they no longer meet manufacturers' specs. Those parameters can be viewed on a curve tracer, and then compared to a known good device, or to the semiconductor datasheet, to determine whether the device is good or bad. Another use of the curve tracer in repair work, is when an unknown semiconductor is encountered (unmarked, or house marked). If the device is still good, its parameters can be determined, and a suitable substitute (commercially-available) device can then be found. More detail on the role of curve tracers, vs. other test instruments, is in the document at either, plop.phys.cwru.edu/repairfaq/sam/semitest.htm or fribble.cie.rpi.edu/~repairfaq/sam/semitest.htm Some procedures for performing curve traces can be found at these two sites, www.ee.upenn.edu/rca/instruments/Curvetracer/curvetracer.html and www.omen.net.au/~uncle/proj4.html Beyond this, consult the operators' manual for your particular instrument.
QUESTION NO. P120-6: Can anyone provide me any information on the Sencore CR-70 CRT Analyzer/Restorer? I am considering buying one used for 525.00.
I have this unit in my shop, bought it brand new from Sencore when it first came out and I personally think it is a great unit. I have run across a couple of Sony`s it would not restore back in the late 80`s but overall a good unit. Have you called Sencore about used units? $525 seems a little high to me.
QUESTION NO. P1213-10: I need some info on Chipper Check. How much, where to get, what platform is acceptable etc. Is it worth it?
Chipper Check works on Windows 95 and 98. To record the UD numbers on the new sets, required to do any Thompsom warranty work and get paid for doing it. Also it makes doing the alignments etc a lot easier. Be advised there are more than three versions now available, some work only with the older chassis and some only with newer ones.
QUESTION NO. P1012-10: Need a quick go-no go test for power mosfets,are there any available?
AnaTek sells the Peak Electronics HMA20 Mosfet Analyzer for $59. Follow the link for Test Equipment for details.
QUESTION NO. P923-4: Beckman HD-100 meter that needs a new LCD Screen. Where can I get one?
Direct from Beckman, special order per model #, Etc.
QUESTION NO. P729-10: Tektronix 2235 100MHz oscilloscope, where can I find/purchase the service manual?
Tektronix Sales, German Medrano email email@example.com phone +521 629-0066 Fax +521 629-0044.
QUESTION NO. P31-5: I need a source for a Liquid Crystal Display for a Fluke 8020A Multimeter.
Try contacting Fluke for a replacement part. You could inquire at their website http//www.fluke.com/service/getinfo.htm for replacements. The Fluke part number may also have been updated. I got a new LCD display for my 8024 DMM awhile ago, and Fluke's updated replacement part number was p/n# 613398. They may know if this same part number also applies to the 8020 DMM.
QUESTION NO. P212-5: Beckman 310 DMM. The 14 pin resistor network on the "front porch" needs replacing. I cannot find a replacement chip. The numbers on the chip are "3000-310-107" "1699-89-0" "7815 Taiwan" and "B1 8914".
Your best bet is to send it to Beckman. I have three, 310 and you cannot get parts from anyone but them.
QUESTION NO. P114-7: 1956 vintage Textronics Model 545 oscilloscope which is missing the plug in module. Does anyone have a source for parts for these old scopes?
I sadly cannot offer an actual source of plugins for old Tek scopes, but visit http//margo.student.utwente.nl/~wel/tek.htm and place a wanted ad in the Classified section.
QUESTION NO. P69-2: Where can I get a good esr meter?
QUESTION NO. P220-3: Has anyone used an ESR meter? If so how helpful are they, and is it worth it?
Get yourself one! The old approach on testing capacitors with an ohm meter is actually useless except to check for a short. About 90% of the bad caps I've found with my ESR meter check good with an ohm meter. Yes, I have used the "Capacitor Wizard" from Independence Electronics (Independence, MO) and found that it paid for itself within the first month. It is an in circuit checker and from what I have seen it works very well. Cost is about $89.00. I have an ESR meter that I recently purchased. It has been very helpful to me in locating the bad electrolytic caps. It was expensive (about $200.00), but if you do much repair work, I believe you will think it is worth this cost. It has saved me a lot of time and trouble since it will test the caps in circuit without having to remove them from the board.
QUESTION NO. P213-8: My TEK 453 Scope will not show a wave trace. Pilot lite comes on but I don't have any filament voltage. I pretty sure no HV is present either. Anyone have any experience on this model that can help me get this scope going again?
You may want to cut the power transformer loose from the rest of the circuit and check some winding resistances or unloaded voltages. The Tek 453 has a very weak HT transformer and goes short internally. Check the fat caps in the plastic surround by the HT Transformer. the 5 Kv output sometimes leaks. Remove the line going to the HT and see if your output Q oscillates ? No Ht , No heater no picture.
QUESTION NO. P1118-2: The Sencore SC3100 Waveform and circuit analyzer lists for $2995.00. Are there similar units or combinations that can perform just a good a job for less?
About four months ago I bought a Tektronics 465b with DMM, all were completely reconditioned and recalibrated, works perfect. About two months ago I got caught up in keeping up with the Jones and bought a Sencore SC3100, certainly not worth the difference in price. 465b will do every thing the SC3100 will but not as handy.
QUESTION No. P811-2: I have a Tektronix 2432 scope that mostly works, but fails some of it's power on diagnostics. Is there any place to send it for repair that is less expensive than Tektronix?
Look in the advertisements in "Computer Shopper"or "Electronics Now". I've seen repair shopslisted there.
QUESTION NO. P625-7: I came across an EICO (Electronic Instrument Company INC.) Signal Generator model# 324. I need to know the specs on the main power transformer. And there are two tube sockets inside one has a 12av7 tube in it, the other on the copper shielding plate is empty. Does anyone know it's value?
The other tube is a 12AU7. The power transformer secondaries are 6.3 volt filament and a 110 volt.
QUESTION: Does anyone know of a good capacitor meter to test small value ceramic caps for leakage (value between 1000P - 1uf)?
I would consider the Z meter manufactured by Sencore. Checks both inductance & capacitance. Checks leakage to about 500v. Seems reliable and well built. See if there is a Sencore rep or if they have a web site and see if a rep can drop one by for you to test drive for a week or so.