Re: Cleaning the flux: 99.8% isopropyl vs 70% isopropyl + 30% ethanol mix?
Toothbrush or cotton bud. Dip either in your isopropyl then scrub the area with flux. I like to follow up with a cut up tshirt put over the wet area then use toothbrush over shirt to soak up the flux/isoprop solution.
Donomite
Member
Last Activity: 07-21-2022, 06:51 AM
Joined: 12-18-2014
Location: Lafayette,LA
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Re: What is a good de-soldiering iron/tool?
great point stj! I learned the hard way when i first used my FR300. If i have to add new solder to a joint to help desolder.. i always clean the flux away before desoldering. I havent had a clogged tip since. Its extra work but easier than having to drill out a clogged tip! I cringe when watching youtube vids of repair work when they are sucking up all that gooey flux!...Leave a comment:
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Tip Tinning
Hello, I have a question concerning tinning a solder iron tip (T15-BC3 bevel). Is it ok just to tin the bevel area, or the entire 3mm end. It requires a lot more solder to cover the whole tip. Hope i explained this well. Thanks -
Re: Re-capping CD Players...
I love shopping at Mouser! Let us know what brand and series caps you choose please.Leave a comment:
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Re: Re-capping CD Players...
I recap most of my 80's stereo equipment. Take pics and make notes of cap placement. Keep it simple. I disassemble the whole unit and wash boards with meen green and isopropyl alcohol. Good luck!Leave a comment:
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Re: Tektronix 2236 scope
Thanks for your reply stj. I finally got it apart. I used my right foot with a shoe on and pushed from the rear while holding both handle cams. It finally broke free.Leave a comment:
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Tektronix 2236 scope
So yesterday I brought home a working Tektronix 2236 scope for free! It lived its entire life offshore on a oil & gas platform (salty air). From what I can tell with limited scope experience, it's operational. The switches and controls are in need of cleaning. So I tried to remove it from the case but can't get it out. It seems to be very tight at the front faceplate end. I've pulled, pryied and hit it from the end. Does anyone know of a way to get it to come out. I even thought of removing the faceplate but am scared of that. I have no choice but to get it out because the controls are so... -
Re: Rotel rack component wiring
Yee ha! Just finished up a 60 electrolytic recap on preamp. I also replaced 3 transistors on mc /EQ amp board. Retouched a bunch of solder joints. Just plugged in preamp and it powered up so then connected it to amp and the source was rush from my phone. IT WORKS!! Right channel not fading out anymore. This was my first attempt at anything this major. I soldered back about 20 wires that had been twisted around the post. I had every board out of this amp. Thanks for all the help!
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Re: Rotel rack component wiring
Thanks for the good info and tips budm & stj. Got the iron hot. Working on power supply board first.Leave a comment:
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Received my lovely new Nichicon caps
Received all caps for preamp today. Only problem I see is the very small size of (10) 4.7uf 25v MW series caps. Several of them are for the filter amp circuit. They are 4mm x 5mm. The existing caps are 12mm x 20mm. I realized when placing the order that they were smaller just didn't realize the new ones would be so tiny. Question is will they be ok? ThanksLeave a comment:
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Re: Rotel rack component wiring
Thanks man. It's in a gorgeous cherry laminate cabinet. My father was so proud when he bought it but mom was super mad at him $$$$ . It's been sitting at his camp for the past 15 years with the camp falling apart around it. So happy to have it home with me. It was filthy and moldy. Spent one week removing face plates and all cleaning it. I will try and get some pics up. I appreciate all your help! I will get the preamp back together and functioning....Leave a comment:
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Re: Rotel rack component wiring
This is a complete rotel rack system. Amp RB-2000, EQ RE-2000, tuner RT-2100 and cassette deck RD-2200. Turntable RP-9400. Preamp of cource. Four BIC TPR 200 speakers. Father bought it new in 1984. Before noticing the problem with the preamp I figured out how to wire it up correctly I think lol . Went preamp out to EQ in then EQ out to amp in.Leave a comment:
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Re: Rotel rack component wiring
ok cool! As I remember...I first noticed the problem in just one speaker. I found another 912 with the same problem (Q139). This is so much fun! Oh I also got way ahead if myself and cut loose a lot of the wires rapped to post, especially on power supply. My plans are to solder back to post. I already practiced soldering to the post after lightly buffing them first with Dremel wire wheel. A lot if work ahead of me. Leaving to go offshore tomorrow for work for about four days. Will have Internet access though. Did I mention that I think I messed up...Leave a comment:
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Re: Rotel rack component wiring
Q136 on MC head amp /EQ board. The schematics are confusing..I wish it was as looking from the component side. I went ahead and placed order for the caps. I can order transistors from local supplier (Ralph's). Thanks!!...Leave a comment:
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Re: Rotel rack component wiring
Happy New Years! I managed to get all caps for preamp in mouser basket. I really need help finding transistors on mouser site. For ex. 2SA912. I found some cross ref (BF435 & 2N3930). I can't figure out how to find a matching transistor on mouser. Help please!Leave a comment:
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Re: Rotel rack component wiring
Thanks a million...that's the kind of information I really needed. I can't wait to get some new caps in. Please stay tuned as I will be needing more guidance....Leave a comment:
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Re: Rotel rack component wiring
Thanks budm, I do have several copies of that manual that I printed last week. Is there a reason that the caps aren't listed on parts list. I know the cap info is on the schematics and actual cap. I have made a list if all can caps but am struggling with the mouser site. I will have to call them. I am excited to do the work but overwhelmed also lol. Thanks...Leave a comment:
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Re: Rotel rack component wiring
rc-2000...Leave a comment:
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Re: Rotel rack component wiring
Ok guys I need help cross referencing components to mouser site. I have a transistor with open base to emitter. Number on part is A912 (R) 72. I think it's 72. I plan on replacing all caps in the preamp. The main issue with preamp is intermittent output to speakers. Removed preamp from loop and used EQ and amp. Works fine without preamp. This transistor came from the MC head amp & EQ amp circuit board. ThanksLeave a comment:
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Re: Rotel rack component wiring
Thanks stj. I actually got some info from the Internet and used the tape 1 monitor input and output. So I went preamp tape monitor out to EQ in, then EQ out to preamp tape monitor in. It's kind of confusing with all the selector switches on the preamp but I think it's Working.Leave a comment:
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