i had the day off, so i took my dad's broken radio apart to try and fix it. thought anons might appreciate it, since this thing is literally older than me. anyway the station doesn't change at all when the knob is turned (even though the frequency indicator on the front side moves normally). the pulley string seems to be intact, but i'm clueless to why the station remains unchanged. can some radio guru point me in the right heading.
>>2976481without sounding like an asshole.you are in over your head.
>>2976481Watch a hundred episodes of Mr. CARLSON'S LAB
Mercury level is low
>>2976481watch shango066bandersentvradiotvphononut
abort abort
>>2976504fair. well i managed to confirm few things in the process:> the pulley thread works ok> the variable capacitor rotates with the knob> frequency does change while rotating the knob (opposite to what i thought earlier)> audio is faint on one station - non audible on all others - almost normal on the strongest station> non stop crackle for as long as radio is on> plugged external headphones, same crackle, same faint audio> most if not all caps are not leaking or bulging>>2976522>>2976509yeah but unless you do contribute something, my guess is you don't know any better neither
>>2976481Half the old radios that have your symptoms it's just corrosion on the coil and/or dirt making bad connections on the board. Use contact cleaner and work the knobs back and forth after vacuuming the whole thing and cleaning up any obvious debris on the board, 2/3s of the time that will do it. If there are any corroded connections resolder them and it should be fine.
>>2976531this >>2976504and this is me >>2976522 careful skippy >non audible on all others - almost normal on the strongest stationattach antenna>non stop crackle for as long as radio is oncrackle or static? static is normal in old radios.if crackle clean pots with deoxit.>most if not all caps are not leaking or bulgingmeaningless on old radios they have to be tested with an actual old timey capacitor tester.you do have one right? no? well you will need one. I suggest a heathkit vintage capacitor tester.
>>2976537>coili brushed and vacuumed the board. the coil has no contact points. it has multiple winding wires branching from it and soldered to the board. with a varying capacitor attached to the knob to cycle frequencies. at the top left is a mode select knob for switching between am/fm bands. touching it can affect the crackle coming out.>>2976554>attach antennait's attached. moving it or extending it did not change symptoms>crackle or staticit's constant crackle that won't let for as long as radio is on. increasing volume to max slightly increases crackle. >you do have one righti have a multimeter but will obv need to de-solder each cap to test its capacitance. >this >>2976504>and this is me >>2976522sorry. i just wanted to fix it for my dad. it's simpler buying him a radio that isn't 40 years old (literally) but it's not the same. anyway thanks for the tips.
>>2976568>touching it can affect the crackle coming out.clean inside switch with deoxit. check for cold solder joints.>i have a multimeternot the same. capacitors can indicate good but are still bad. you need an actual capacitor tester.
>>2976568>anyway the station doesn't change at all when the knob is turned (even though the frequency indicator on the front side moves normally). the pulley string seems to be intact, but i'm clueless to why the station remains unchanged.Be sure the white nylon wheel rotates when you move turn the knob to change stations.Be sure the silver shaft is fitted inside the white nylon wheel and the shaft turns with the wheel.The part on the other side of the board connected to the shaft is what selects the station.
>>2977359I know nothing about radios but this topic is super interesting.>>2976554Keep helping OP if you can.
>>2977597i didn't have deoxit, and not sure if 70% ethanol is appropriate, but will attempt to clean the mode select, volume and tone knobs, (they do crackle when touched so there's probably bad contact). maybe even inside the variable cap.what i found so far are leaky caps. one when tested in circuit produced a continuous beep but not sure if the cap is shorted or some other parallel component is responsible. i ordered me some soldering tools which will arrive on tuesday.
>>2977359yes the wheel, pulleys, and variable capacitor all connect and rotate ok. that was first thing i checked when my dad told me it only runs one station. but the stations do change, it's just that the audio is too faint, with constant (frying pan) crackle and overall just terrible. the stations that still runs is probably the strongest signal.
>>2976537This sounds likely. Autistically clean every connection with a small wire brush using all your spare time for two months.
>>2977696Those caps are not leaking. That's just some glue they used for some reason. I've seen it before in very old electronics
>>2976537>>2977725i did clean:> mode select contacts> volume potentiometer > tone potentiometer > inside the variable capi found this resistor that should be at 82k but instead it's reading around 120 ohms on the multimeter. could be something. it's situated right by the connector for the front volume needle.>>2977732ok that's good to know. but the shorted capacitor is definitely shorted right?
>>2977761Do you have a schematic of the circuit? I would advise against measuring things in circuit. Besides, a resistor is unlikely to fail and I would expect it to burn up if it did short. Electrolytic caps are the most likely to fail and cause issues, and they will even keep showing their rated capacitance to a DMM, except they now have a somewhat low internal parallel resistance. My last repair was due to such a fault: a cap allowed DC to pass and drop, and it pulled the power rail slightly down enough to cause problems, but not enough to be obvious. The fucker blew on the bottom too instead of the top, and I found out only when I had no other option but to desolder every cap to measure it individually to find the obvious but otherwise hidden failure. Transistors are close second to be the ones that release the magic smoke, but something must have likely gone wrong somewhere else for it to happen, so they might be more of a symptom than a cause.
>>2977793>Do you have a schematic of the circuit?no and i've looked. my first image of the pcb is the closest thing to it. but all resistors measured in board were as close to their color coded values as possible, except for that one >>2977761it's a toshiba rt360rhttps://www.youtube.com/watch?v=P8IzBZ8hEH4
last clean up yielded results. I get stations now! Hopefully it won't fade out again. I still want to tinker with it. try to replace the cap and resistor as soldering practice. will come back after i break it again.
>>2977761>but the shorted capacitor is definitely shorted rightI can't see from the picture if it is shorted or not. Maybe it is in parallel with the center terminal of the potentiometer. Try rotating the potentiometer to the opposite position and check if the capacitor still beeps continuosly
>>2977832>solid stateThey actually insisted on stating that it was not made with vacuum tubes
>>2977869>I get stations now!>>2977869>I still want to tinker with it.If you have it working, STOP.Tinker with something else.
>>2977889it's working fine now i guess so i won't be going in there again.my soldering tools were delivered to me last week. plugging that hot iron and watching the initial plume of smoke come off it as it burned through factory gunk scared the shit out of me.then i finally summed up the courage to get a feel for it, and then started getting more comfortable around it. planning where and how the cable was going to be positioned while handling the iron, like i was guiding a tree through a table saw.
>>2979546i didn't know what to work on, the first broken thing was my redragon mouse, so i took it apart, cleaned it and identified the type of switches it had, then ordered me some replacements.desoldering was a bitch. even with flux, and wick, it took me forever to get the broken switches out. it didn't help that i was so paranoid about inhaling lead that i was doing deep sea breath holding throughout the entire time.finally got the old switches out after nearly burning a hole into the pcb, then i put it the new switches, which was about 5% of the difficulty of getting old solder out (i think they use low lead solder in the factory or at least that was my cope for why it took so long).in the end i couldn't believe that i fixed that thing, it felt new and responsive, no more double clicking or missing clicks.
>>2979549after first success .. i figured might as well fix my earlier mouse from 2015, the left button was completely dead, and the scroll wheel was unresponsive, so i did the same thing. got matching switches, and got to working. surprisingly it took me 30 minutes to replace the switch. the scroll wheel i managed to fix by bending the metal contact and cleaning inside the encoder with alcohol.
>>2979552and then my old LG cd rom. it wasn't reading discs, detectable in bios, or ejecting smoothly. i had already replaced it 6 years ago.i got it brushed, vacuumed and oiled. tried to diagnose if it wasn't getting power, it was. some diode was reading 0.5v - 0.8v in both directions. i desoldered it to recheck then soldered it back.cleaning the laser emitter made it read discs again. and dunking the rubber band in hot water and cleaning it made it get better traction, so the door was opening more easily.
>>2979554finally, i plan on replacing my computer case power switch tomorrow. it needs to be pressed multiple times, at a certain angle to work. wish me luck.
>>2979549>i was so paranoid about inhaling lead60/40 solder melts at around 360°F - 460°F Melting doesn't put lead fumes into the air.Lead boils at 3180 °F -- you're sniffing flux, not lead.I'm 83. I've been sniffing flux since I was 15. The only thing wrong with me is I still come on 4chan.If you're really worried, get a fan to blow it away from your face. You don't need clean-room conditions to solder a switch on a circuit board.
>>2979558>I'm 83all the proof i need. thank you kind sire for explaining. i dedicate my thread to you.
>>2979560NTA, but wash your hands properly after you're done. Ingesting it is going to get you way more than sniffing it.
>>2979558>Lead boils at 3180 °F -- you're sniffing flux, not lead.All metals have some vapour pressure...But yeah, I agree. The smoke is mostly flux, which btw I have been inhaling since I was 13. Since alive
an update on my noob soldering journey, i made a stupid ass mistake today while fixing my case power switch. first of all. desoldering is still a bitch, taking 98% of the job time. the wick doesn't pull out solder from inside the holes. yes i do tin the iron, and add some solder to help with heat transfer, but the component stays clung on after clearing most of the 'exterior' solder.im embarrassed that most components i desoldered did not come out in one piece. having to use pliers and what have you, and do hand acrobats to just get the fuckers out of the hole, only to have to use pins and needles to clear out the hole further. my mistake today was adding enough solder to secure the legs, but as you can see in picrel, the legs weren't making contact with the pads at all. I connected it to my pc, pressed the button but nothing happened. 5 minutes later with a multimeter made me realize there was no solder connecting the legs to the pcb in the first place. >>2979588>wash your hands properly afteryes ofc i even wipe any tools or scissors i use with alcohol.>>2979672>The smoke is mostly fluxok but on some forum they say it's the flux inhalation you should be worried about, which is the total opposite of the advice im getting from anons.
>>2979710>. the wick doesn't pull out solder from inside the holes.You need flux. Either add flux or buy wick with flux impregnated into it.You need flux with solder. You can't solder without flux.>s the flux inhalation you should be worried about,Soldering OR lungs. Not both.My suggestion would be to open a window or get an extractor that goes outdoors. and take a breath before you start so you can blow fumes away from you as you go.
>>2979712>You need flux. Either add flux or buy wick with flux impregnated into it.i am using flux! i dunk my wick in it beforehand, and add it to joints before starting.but between the pressure of the legs gripping onto the pcb, and the remainder solder inside the holes, the thing stays stuck. if i had a third hand, i could pull the component out, while the iron presses the wick onto the joint.>>2979712>Soldering OR lungs.i've been breathing fumes for a week straight. today i fixed my pc case fan controller and power button. i didn't have the ludicrous 9mm tactile switches so i super glued some plastic on a 5mm tall switch.
>>2979827>if i had a third handUse a little screw driver. Slide it under the leg of the component and melt the solder on the other side with the soldering iron. When the solder is liquid, twist the screw driver.This is how I' been dessoldering components since the age of 13. Could never make the wick work, just like you. No pun intended
>>2976531As>>2976522 said watch Shango, you'll learn more from that guy than any of the "restoration" fags, as for the noise it's probably shit caps, if the caps ate the PCB your gunna have a bad time. Biggest thing after replacing bad caps is deoxit pots and alignment. A shitty frequency generator should be all you need for alignment maybe a scope if you want to see more
>>2980882it's been running ok since the cleanup. im tempted to change the caps but i've moved on to fixing other things.>>2980482>Use a little screw driver. Slide it under the leg of the componentthat checked out. thanks. i got me some new capacitors for my 2007 atx power supply that fails under load. there's still more caps not delivered, but i already began swapping the ones i have.
>>2980906i had two problems swapping the caps today:1) the (-12v) blue wire literally came off while moving the pcb around, and i freaked out trying to find where it should go. i could see a little remnant of wire sticking out and a little (-12) print.i managed to solder the blue wire back, without shorting it to nearby components, only to realize that both live and neutral ac wires now came off as well.b) when i was finished, i measured voltages, and the yellow wire which is supposed to have (12v) had only (9v). internet said add load to the psu to get full voltage, but even then it remained at (9v). i didn't find any shorts between the dc rails, or between the caps positive side and ground. ultimately i found one (25v) capacitor leg was loose, so i melted the solder and added more to secure it. now it had 12v again.will do the main caps tomorrow when they arrive.
>>2979710I had to desolder a bunch of RAM from a Commodore 64 to test it* and put in sockets**. 8 chips, each with 16 legs. I used a solder sucker. It is basically the manual version of a desoldering tool. Much better than a wick, in my experience. Not 100% perfect every time, but way less issues than when using a wick.*Fun fact: early Micron Technology RAM used dogshit chemistry and has a very high failure rate after a few decades. Early micro computers, like the C64, Apple II, Atari 8-bits, etc., all used them and it is a common cause of them not working anymore.**Fuck Commodore and their cheap-ass leadership. Apple and early Atari computers had socketed chips, which makes servicing their machines a lot easier. Jack Tramiel wanted everything as cheap as possible so they mostly soldered chips to the board. He did the same fucking thing when he took over Atari in '84.
>>2980910You should strip back those wires that broke off a bit and see if any corrosion wicked up under the insulation, shouldn't be that hard to replace if so
>>2981018>shouldn't be that hard to replace if sooh it was far more disastrous than that. today i received the second patch of capacitors, so i grabbed my iron and went to work. after replacing everything, i put the pcb back on, and turned on ac power with green/black shorted. except the fan didn't turn on. i took my multimeter and measured around:> ac line: had power.> fuse: had power. > rectifier diodes: .... BANG!the probe shorted two diodes, and flew sparks into my face with a loud pop. fuse burnt and foggied up instantly...i realized that the psu was in fact running, and the reason the fan wasn't spinning, is that the red wire in picrel, detached from the 12v rail joint at the back of the pcb. meaning the power supply was working and ready, but now the fuse and possibly the diodes are forever fucked.
>>2981029i looked through my stash for a fuse. found a 10a - 250v fuse, except it wasn't the through-hole kind (or the right value). so i soldered some copper wire to it and put it into the board. i know a 10a fuse might as well be a shorted wire, but i was desperate and needed this thing to finally work. you can see how sketchy it looks in the photo with its improvised legs hiked up.measuring voltages checked out for all rails, but still not sure if it's safe to plug into actual components.
>>2981031>measuring voltages checked out for all rails, but still not sure if it's safe to plug into actual components.The 'components' are expecting a certain voltage. If the voltage(s) are correct, it should be fine.Have you looked into converting it into a bench supply?Not sure if you'd need something like that but there a lots of YT and other sources on how to do it.
>>2981049>Have you looked into converting it into a bench supply?that's actually a really good idea anon, thanks a lot. i have 5 PCs at home as part of a render farm, so it's always good to have a spare. but the bench supply idea is worth it.
>>2981049>If the voltage(s) are correct, it should be fine.i connected it to my pc, and put maximum load on the cpu for 15 minutes. no restarts or crashes. it looks like i've finally fixed the thing
>>2981132went to try my luck fixing something else today, but i'm finally at a brick wall.my old cctv ptz camera was damaged by rain few years ago. just found it one morning not working at al and set it aside till today> disassembled > cleaned the main pcb with ethanol. > connected dc jack to 5v. > slight smoke coming from power input area > diode / capacitor near the dc input jack are burning hot> on second try, the cap and diode weren't heating up anymore> camera wakes up, and starts moving back and forth then goes to default ptz position > very faint IR light can be seen from the IR blasters (abnormally faint)> camera isn't detectable neither on the router through rj45 jack or by wifi and app> resetting doesn't do anything> i measured voltages around the main pcb, and they're mostly 5v in various parts, except for the big chip area funnily named gRAIN, voltage there is about 1v. > the diode area where the cable connects to the upper compartment for the ptz motors and camera (where it says d41 - d51 - d61 - d71) all measure 5v> there's no short between vcc and ground. it measures about 350ohms> diode near dc jack measures 0.1v in both directions but this is because of the capacitor sitting parallel to it.> i reseated the ribbon cable multiple times> measured any voltage coming from the antenna connector (the grey cable) and there's some random ripples happening. > the area where the rj45 jack connects to pcb has 0 volts this is obviously up and beyond what i can do on my own. and for all i know it could be a software problem or firmware chip going bad.
>>2981135>diode near dc jack measures 0.1v in both directions but this is because of the capacitor sitting parallel to it.Unusual for a diode to have a capacitor parallel to it in a DC circuit.The capacitor should not affect resistance after a few moments. It should bleed off the charge induced by the meter and read open or very high resistance.I would pull the capacitor and test it out of circuit.I like to use a light probe (pic related) to test diodes. Lights up one way, doesn't the other.
>>2981145i wanted to replace the diode, but don't want to damage things further. the capacitor has near 0 resistance with ground on one end, and about 96ohm the other way i think. i found the datasheet for the brain chip. will try and measure if correct voltage are available on all pins.https://dashcamtalk.com/cams/b1w/GM8136S_GM8135S_Data_Sheet_V0.2.pdf
>>2981149i measured around the main chip for missing voltages, 3.3v and 1.5v are missing. only 1.1v is there.> pin 9 should be 1.1v -------- reads at 1.1v> pin 68 should be 3.3v ------ reads at 0.7v> pin 93 should be 1.5v ------ reads 0v> pin 101 should be 1.5v ---- reads 0v
>>2981164here it is with the chips identified. I don't see where power regulation is located or what's failing?also measuring resistance from main chip pins to ground:pin 68 (3.3v) to GND -------- 2kohmspin 93 (1.5v) to GND -------- 3.2kohmsso there's no short?
not sure if i found the fucker. these are voltage measurements on the back side.
>>2981171the datasheet of a similar regulator has the pinout as follows:pin1 Enable control. Pull high to turn on. Do not float.pin2 Ground pin.pin3 Inductor pin. Connect this pin to the switching node of inductor.pin4 Input pin. Decouple this pin to GND pin with at least 10μF ceramic cap.pin5 Output Feedback Pin. Connect this pin to the center point of the outputresistor dividerso is the step down regulator itself bad (the one marked a121), or has the resistor that feeds into pin 1 stopped giving it proper value to adjust the regulator to 3.3v?
good and terrible newsi managed to get the 3.3v and 1.8v regulators to enable by shorting a wire from 5v to each en pin per regulator. finally i had correct voltages show up, the camera was making sounds, i could hear the ir cutoff filter kicking in and out, and the ir blasters were on full brightness and responding to lighting conditions. even the speaker was popping.it looked like i fixed my camera, so i went to solder diodes between the two points but the area was so small that one of the regulator pins got detached (en pin) so now it's over and i won't be able to fix it without a replacement that i can't find.i thought about buying an actual buck converter chip and wiring it directly to the 3.3v and 1.8v rails, but at that point it would feel like brute forcing the problem instead of working through it, and i have no idea if that would even work.i had it running anons. it was supposed to work.
ok i managed to use whatever was left of the broken en pin to deliver the enable voltage from vin into both buck regulators. it looks like shit but i finally got correct voltages to the main chip!
>>2981353got light!
>>2981354it's alive!
>>2981355
>>2981355>it's alive!>>2981356
>>2979710>ok but on some forum they say it's the flux inhalation you should be worried aboutthe flux in you electronic NOCLEAN solder is most likely rosin based, that is tree resin. That stuff is acidic at soldering temperature and contains mild allergenes / irritants. a few huffs will do literally nothing.not to confuse with plumber flux, acidic flux, brazing flux
