I wonder what the squarewave would look like with the original parts in that
@user-jt9qb6dj8x3 ай бұрын
Look up flea power Magnavox Dave Gillespie. He shows the oscilloscope waves before and after his modifications
@larryshaver35684 ай бұрын
on the power cord where does the neutral go?
@2008alde4 ай бұрын
I just have a simple question if that exists. I have a Sony TA-4650 which until recently performed nearly flawlessly. The other night I wanted to play an LP and within 30, the speakers cut out. the unit recycled and then I played something through the AUX input and it was fine. Went back again to the phono selcetion and BANG.. speakers went out again. If I have anything connected to the phono input but dont feed it an active signal, like playing an lp, I can hear from one channel that fluttering sound. Could I have damaged the phono stage and is that something that could be repaired?
@adaboy4z4 ай бұрын
What size lamp is the power button?
@adaboy4z4 ай бұрын
I must have an older 4650 because the speaker relay switch is vertical and where you have plugs I have wire wraps? Also you have a capacitor your power supply board that is absent on mine. In its place is a transistor.
@rogeronslow14985 ай бұрын
How can you do any analogue design without an oscilloscope?
@woofer95886 ай бұрын
Did you ever do any more videos on the Pioneer SX-1010?
@stinkenstine6 ай бұрын
Excellent video on the Legendary SX-1010.
@alanpecherer57059 ай бұрын
Kind of an unusual piece of gear. I would be torn between restoring it to its proper function, with all the precision, and knowing that for the most part, there is almost no application that requires or even benefits from such precision.
@brannonmcevers185410 ай бұрын
Great job👍 working through the schematics and using proper logic to find the root of the problem. YT needs more techs like you to show proper electronics Ttroubleshooting
@R.Akerman-oz1tf10 ай бұрын
I suspected an "open". Well I got lucky due to poor soldered Xstr.
@larryshaver356811 ай бұрын
i have one of those, i see 4 ohm speakers are becoming more common again
@boonedockjourneyman7979 Жыл бұрын
Great work. I ended up with 13 Power Designs supplies. I was going to start fooling around with them in August. Your effort here helps me immeasurably.
@cyrilratnasuriya3593 Жыл бұрын
Pls send me Pioneer GM -222 car Amplifier mother Board Price available
@thebast2748 Жыл бұрын
Hi. what company made this 1.5k resistor?
@richbrown5852 Жыл бұрын
Would this work with the 400w 6550/kt88 ppp williamson design?
@davidkclayton Жыл бұрын
When you have fluctuating voltages manually set the range, on the DVM to eliminate auto-ranging annoyances.
@musicstevecom Жыл бұрын
Very good video, Still Learning . Did you check the heat after you installed the Tip's? It cool at first than will heat up the board will actually heat up to 128 degrees to 158 wow that's hot? I have the same problem w some Pioneer SX-950 sx850 which has another 2sd313 for the lamps. I found that its not current that heats them up. Its the input of 40vac to 26vdc them to 13.5vdc and w mind also 40vac to 26vdc than a 100 ohm Resistor (Heater) cuts it down to 17.4vdc than to 2sd313 (Heater) to 5.4Vdc -6.4vdc After recap. looks like a bad design?
@kbkman7742 Жыл бұрын
Just 2c... You could induce oscillations just by the fact you have everything out on a benchtop without a chassis, with leads running every which way. Sitting transformers one way or moving them a couple of degrees can upset stuff too.
@dell177 Жыл бұрын
Those 200 ohm resistors should be fed from the same source. Feeding one from the others output can increase your problems.
@messingwithelectronics7462 Жыл бұрын
I had the same thought, however I tried it in both configurations, and there was seemingly no difference in stability. But feeding one from the other gives lower ripple since the two filters are in series, so I chose that.
@dell177 Жыл бұрын
@@messingwithelectronics7462 i learned that practical experience often trumps theory decades ago!
@jimcatanzaro7808 Жыл бұрын
I have the A9-c it sounds great when you put a signal in it but I hear alien noises when at idle and it’s annoying I might have to make a shield any thoughts
@messingwithelectronics7462 Жыл бұрын
It's worth taking a look at all the grounds and making sure they're good. The RCA shell to chassis ground was problematic in this A-8A. After shooting this video I added a spade lug from the RCA shell to the chassis and it reduced EMI pickup substantially so that the higher-gain inputs weren't swamped by EMI.
@messingwithelectronics7462 Жыл бұрын
How loud are the noises? Do they occur even with signal input but they're just masked by the signal?
@trangvuitinh9003 Жыл бұрын
Bạn phải thay thế điện trở r13 và điện trở r14 bằng nhau và bằng 1,5 k ohm như thế nguồn mới cân bằng + - 24v như nhà sản xuất thì hai điện trở này đang khác nhau r13 = 1,2 k ohm , r14 = 1,5k ohm như thế đo điện áp 24 v ko cân xứng . Và bạn phải thay tất các transistor loại a và visai a 726s trên bo công xuất và bo chỉnh âm sắc bass , tress , các tụ 2,2 mf nối tầng , bo bảo vệ , bo radio , b sẽ có môt máy thu tuyệt vời .
@jernejkurincic9050 Жыл бұрын
I've never seen so low value resistors in tube amp power supplies. 1.5k is quite ordinary, up to 20k easily ... But it's not only resistors, this is caused quite probably with too much of capacitance (you made a big slow oscillator). I've first heard of motorboating when somebody wrote that you should avoid too high capacitors because of it ... But I am too ignorant to be sure about it.
@robnic52 Жыл бұрын
The very audible slow, 'blat, blat blat' motorboating noise coming out the speaker Is most often caused by a bad ground connection on the negative end of the power supply filter caps. Dry solder joints or a ground connector lug not tightly or cleanly bolted to the chassis. The filter caps can't pass sufficient amperage to ground, they begin to charge up but then collapse so setup a regular, high voltage (intrusively loud) pulsing. This seems like a lower frequency parasitic oscillation. Lead dress can cause it, it might have been interesting to try suspending some grounded tinfoil over the wires sprawled all over the table to see if the oscillations stopped. I can't see enough to read your finely drawn circuit diagram and component choices so pls excuse me if my comment is unrelated or unhelpful.
@barrybreaux5303 Жыл бұрын
Do you have your old oven? Where did you get the zener diodes? All the resistors in my oven were crumbling.
@messingwithelectronics7462 Жыл бұрын
I bought new 1N823 Zeners with a similar voltage: www.mouser.com/ProductDetail/494-1N823. I thought they were the same ones because the part number is very similar. However, I think the voltage is slightly off, which is why the whole thing has a slight voltage offset that the adjustment can't fully get rid of. Honestly I think I might have lost the old oven. Thought I saved it but can't find it now.
@barrybreaux5303 Жыл бұрын
I was was thinking about simulating the oven circuits with available Zener diodes. I was able to take my oven apart. The bracket that held the thermostat in contact with the internal chamber was broken. I think the chamber got way to hot burning up all the clay coated wire wound resistors. One of my Zener diodes is bad. I will have to un-wind the heater element to weld the bracket back together. But I think I can fix it!
@messingwithelectronics7462 Жыл бұрын
@@barrybreaux5303 That's impressive, I did not have the stomach for all that work! But I hope it comes together. Retaining the original oven is definitely the only way to achieve the original performance.
@barrybreaux5303 Жыл бұрын
Retired electrician engineer. I have to be challenged.
@messingwithelectronics7462 Жыл бұрын
@@barrybreaux5303 I found my oven! If you want it, I can ship it to you. I'd list it on Ebay for .99c plus the shipping cost (like $4). I can continuity test the heater if that's the part you need.
@lukegeis6491 Жыл бұрын
That is a metric butt-ton of filtering for what you have going on. Too much of a good thing is still too much... There is a mathematical solution to this. More or less, X capacitance requires X resistance for X filtering. It is not an arbitrary number. I can't give you a number off the top of my head,, but, it is an easy-to-find number on the interwebs.
@messingwithelectronics7462 Жыл бұрын
Yeah, I did model it in PSU Designer II and it's very overkill. This design is kind of nostalgic for me because it's based on an old Capehart amplifier I restored that also had a huge choke, so I wanted to replicate that 1940s look and feel. Cheers!
@josephsirois2353 Жыл бұрын
I’m working on a ten-ten currently with the same issues , thanks for the suggested parts list and video
@georgem.6136 Жыл бұрын
Awesome Video!
@alexandres8846 Жыл бұрын
Good job and it is an obligation to change the electrolytic capacitors of devices over 20 years old.
@BinuMadhav Жыл бұрын
Hi, Nice video. I have recaped my SX1010 and now its powering on, but relay is not actuating, so output is not there. What could be the possible problems? Kindly reply. Thanks in Advance.
@musicstevecom Жыл бұрын
Check all wire wraps they can easy break or come loose, also clean the back of the board which is a good time to check for bad solder joints, Bad traces and also re-solder the post which can have cracks in them, Also check for missed new leads that were forgot to solder, double check oration of parts replaced, Good luck
@heri7299 Жыл бұрын
Do you maybe know how to voltmod memory on this thing? I can't find anything on youtube or forums
@edwardallan197 Жыл бұрын
I have seen index knobs with a keyed sleeve the set screw hits. This binds the assembly securely at any clocking. While still satisfying the flatted pot shaft.
@messingwithelectronics7462 Жыл бұрын
That's a good idea.
@edwardallan197 Жыл бұрын
That amp is appealing as all get out! Thank you for sharing.
@jf-3945 Жыл бұрын
IF time allows, I'd be interested in the software/firmware to inject a tone and do output harmonic analysis. Shall look for ideas and I also appreciate the effort you placed in restoring a Heathkit amplifier. I ask because an HP analyzer goes for considerable amount of money even today. Just love your simple set up. The stereo on left looks like a Pioneer? LOL Again, thank you on behalf of us on your channel. Well done. I learn a lot from your experience.
@messingwithelectronics7462 Жыл бұрын
Yes, the receiver on the left is a Pioneer SX-1010! Repaired in one of my previous videos -- it's awaiting a full restoration, but I'm more into tube stuff at the moment. Great idea; I will definitely do a video on my test setup. It is very simple: an SMSL M500 DAC and an E1DA Cosmos ADC with a computer running Room EQ Wizard. The DAC functions as a sig gen and the ADC is the spectrum analyzer. The E1DA cosmos is really a great piece of equipment. For less than $200 you get THD and noise performance that rivals audio analyzers costing $10,000+. It can handle much higher input voltages than a standard soundcard solution thanks to built-in attenuators; the speaker input goes up to 43 volts! Performance is also far better than soundcard/audio interface ADC implementations. The main downside is no built-in calibration (must set cal levels in REW).
@jf-3945 Жыл бұрын
@@messingwithelectronics7462 Thanks... That video led me to you as I am trying to repair my SX-1010. Cheers
@KingZeusCLE Жыл бұрын
I would say this video is well done. I know it's a couple years old at this point, but wanted to say thank you! This is much help in the current GTX 260 Comp for a first time modder.
@heri7299 Жыл бұрын
Hi man, i have the same pcb and i can't volt mod my memory do you know how to do it?
@cletusberkeley9441 Жыл бұрын
Excellent explanation of the phenomenon. Very innovative and cool breadboarding technique.
@bradelias9292 Жыл бұрын
Could you share your parts list?
@josepheccles9341 Жыл бұрын
I see you use relay sockets for prototyping like I do. Super cool.
@hernancoronel Жыл бұрын
Totally love this mess! Congratulations!
@t1d100 Жыл бұрын
A clear explanation and demonstration of the problem.
@KeritechElectronics Жыл бұрын
Clever of you to use octal relay sockets for prototyping. I've taken a much more traditional approach with a wooden board and sockets mounted on L-brackets. It's a very nice explanation of motorboating :) and it will occur in class AB or V amps with high-Z power supplies (e.g. tube rectifiers, thin wire on power transformer) if the voltage sags under load.
@KeritechElectronics Жыл бұрын
So, if this is 4010, then is it twice as good as 2005? Hell, it's twice the voltage and twice the current. Quad Damage! :) Looking at the panel, it reminds me of Nagra recorders. Every single detail here is fantastic. This PSU is absolutely freakin' BEAUTIFUL on the outside, a bit chaotic inside. Made with good quality components, maybe save for electrolytic caps (I don't trust them), obviously very high end gear. Down to a millivolt, soooo damn nice! I've never heard of oven stabilization in PSUs. And no PCB, all turret board like those old vacuum tube guitar amps, haha! A joy for ever. I like your oven replacement mod, keeping the PSU fresh and going :)
@messingwithelectronics7462 Жыл бұрын
Thanks! Really did not anticipate spending so much time on this thing, but the front panel is too beautiful to sell it as a parts unit.
@erbalumkan3692 жыл бұрын
When you do the voltage measurements on the pins of the vfets (vfets not yet inserted), what do you use as reference? Chassis ground or speaker ground?
@HipocratesAG2 жыл бұрын
Very nice trip by the schematic!! Awesome content.
@erbalumkan3692 жыл бұрын
Be careful when you change the power line voltage setting with the multi-plug. Two female pins broke off internally when i tried this. The pins are very weak design. I managed to solder the broken parts onto the pins again.
@indian.techsupport2 жыл бұрын
couldnt you just use 2 opamps?
@messingwithelectronics74622 жыл бұрын
Yes, using discrete op-amps would be the better solution but I was being lazy and figured I’d try the board instead. It eliminates the need to breadboard or make a PCB. Most of the Ebay differential op-amp boards are designed for audio and I wasn’t sure if their HF cutoff would be too low since there’s no documentation.
@arcticafrostbite6172 жыл бұрын
This video is really interesting. this is all really neat.
@messingwithelectronics74622 жыл бұрын
Ignore the HF noise on the waveforms -- that's not the THAT 1646's fault. It's present when the board is powered down as well. From reviewing scope screenshots after filming the video, it's clear that the "square wave" produced by my sign gen is substantially more square than the "pulse wave," as I suspected. Picture of the square wave: messingwithelectronics.com/wp-content/uploads/2022/08/THAT-1646-Sw-Wave.bmp And the pulse wave: messingwithelectronics.com/wp-content/uploads/2022/08/THAT-1646-Pulse-Wv.bmp
@user-xm6qb5cg4i2 жыл бұрын
2sc869 has many failures
@reynir8448 Жыл бұрын
it's true
@R.Akerman-oz1tf10 ай бұрын
Just past 7 min, it was mentioned: axial replaced radial. Not sure how that would fit(from My viewpoint), but a treasure of a tutorial nonetheless.@@reynir8448
@R.Akerman-oz1tf10 ай бұрын
Duly noted retraction! If I had watched further(time is limited in My viewing) I can see @ the 30 min mark the actual dimensions. My deepest apologies. So sorry.
@messingwithelectronics74622 жыл бұрын
After further testing with signals, I've upped the resistor to 4.7k. The 1.5k would oscillate with a sine wave applied.