Grumpy Techie

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@corvetcoyote443 6 күн бұрын

I just recently discovered these beautiful makers seeing one on the movie Bucket List I am getting one of these real soon.

@Mark_Anthony808 7 күн бұрын

What would cause my pf800 to intermittently stop making sounds? Power light is on. Compressor light activates. Di to foh works. Just stops sending signal to the cabinet.

@thebigtunaboy 19 күн бұрын

I have this amp and it came to me 2yrs ago, with a the speaking making terrible noises, then it blew the TIPs. I replaced the TIP31/32/35/36 only to have it blow again after running for a short while. I also replace a number of other parts including the 3.3k resistors as the were burnt. After 4 attempts at changing and blowing, I gave up. It sat in garage for a while. So I pulled it out again this week. I cut out the TIPs and opened them up as I wondered if they may have been fake, they were. So basically, I had been fitting fake parts that could not take any load, these all came from eBay same seller. So I bought new ones from CPC and now it works fine. Watch out for fake parts folks, it caught me out multiple times.

@doobie8425 Ай бұрын

Have a general question. Is there a way to mod the amp for more power output? My pf 800 goes into thermal protection. Idk why. 2x15 “1,200 watt” chained to 4x10 “800 watt” both cabs 8 ohm. I’m not able to play at full volume. Maybe 3/4. Anything more it goes into thermal protection

@paulsamuels2728 2 ай бұрын

Looking for the schematic please....

@eddiegarcia3202 2 ай бұрын

Still burning up TIP31C. any suggestions?

@firdoshdiakus4841 3 ай бұрын

Useless

@zak87 6 ай бұрын

How is it that it doesn't vacuum up coffee grounds as well?

@fishing_in_blood 7 ай бұрын

does it require vaccum degarassor for removing bubbles ?

@vladtepes481 9 ай бұрын

Why on Earth would bother to put N connectors on RG58. At least upgrade to LMR240. There is little reason to use RG58 at all.

@seanhoward5562 9 ай бұрын

Looks like the slot in front is to help push some of the hot air out of the box, along with the holes in the bottom.

@ericmendez1462 9 ай бұрын

Test with analog multi tester

@sajinss9428 10 ай бұрын

Am searching many times in amazon but no results for buying this product Please give me this purchasing link in Amazon ( am sorry my English is very poor)

@RodPeterson-p1g 10 ай бұрын

Thank You for this vid, it is the exact N type female connector I need to replace and repair!👌

@algazoth 10 ай бұрын

Thank you so much sir.

@alexanderstelly4531 11 ай бұрын

Beautiful

@GregorHuth 11 ай бұрын

im confused on how u got the amp out of the chassis

@lucianoparenti5518 11 ай бұрын

Hi, I have this amp, and I wanted to change the large filter capacitors to improve the sound. I have a big doubt because the diagram does not resemble any amplifier diagram that I know of. I'm definitely not an expert, so I'm asking if I can increase the capacity without compromising operation. Thank you

@GrumpytechieNet 11 ай бұрын

The "sound" shouldn't improve much by larger caps (new caps might help filter out hum better though). On voltage rating, you can go as high as you want, but try to stick within 120% of the original capacitance values, any higher and the inrush currents when powering on can become an issue. When I replace these, I generally look for caps with the same diameter and leg spacing, slightly higher voltage rating, similar capacitance (100-120% of original rating) and the highest temperature rating I can find. Better capacitance tolerance isn't worth paying extra for though, +/- 20% is good enough for big filter capacitors.

@marklbreen Жыл бұрын

Thanks for the video

@elliotsmith0850 Жыл бұрын

maybe someone who knows what they are doing should have done the video.😂

@GrumpytechieNet Жыл бұрын

Try filming something you've done hundreds of times and narrating it at the same time yourself, you might be surprised 🤣 but yeah, I'm not pleased with this video, I might redo it where you can actually see what I'm doing.

@benjamimaugustodequadros2006 Жыл бұрын

Bom dia amigo sou técnico no Brasil , vc pode me informar qual a frequência de trabalho nos gate do fet. No pino 13 do ic 8. Irs20957s, me ajudaria muito. Fico grato pela resposta Good morning friend, I'm a technician in Brazil, can you tell me the frequency of work in the fet gate. On pin 13 of ic 8. Irs20957s, it would help me a lot. I'm grateful for the answer

@GrumpytechieNet Жыл бұрын

Sadly I no longer have this amp, so I can't measure it. However, if the amp makes a clicking sound or makes no sound at all, check if the power mosfets are shorted, they blow quite often. Or is there no voltage present on the main capacitors, check if the power supply switching mosfets are dead or the driver IC is dead. The voltage on the main caps should be around +80 and -80 volts, 150 volts on the PF500

@darksideband77 Жыл бұрын

A lot of People have the same problèm with the fuse

@GrumpytechieNet Жыл бұрын

Yeah, seems so, but I'm still unsure what made it pop like that as I can't find any other problem with the amp, and even shorted FETs in the power amp doesn't cause that fuse to pop as the power supply is very well protected. My only theory is that someone selected the wrong line voltage.

@espacoipiranga Жыл бұрын

Thanks for the video. Gave me some new things to check! Mine works but the volume is too low. i have to crank it up to max to get half the volume of an Ampeg B115 (150w) volume in the same speaker. Checking some voltages I found that i'm getting +80v/-80v where, according to the schematics, should be +55v/-55v. But i cant find anything faulty. I think this overvoltage is burning the R98 and R94 next to the Q10 and Q13. I must be missing something.

@GrumpytechieNet Жыл бұрын

Hmm, I seem to remember that the rails were around 80 volts on mine as well. Could it be a problem with the preamp or that the pad is engaged?

@espacoipiranga Жыл бұрын

@@GrumpytechieNet Humm thanks. It is weird. I think +-80v is suspicious be because of the frying of these R98/R94. everytime they are in. Why would schematic says it is +55? ... Maybe its the revision difference. the pad is the first thing i checked. It is ok. I will check the preamp section now. thanks for the tips

@bryanhenry8075 Жыл бұрын

It will be a light flavor unlike my French press where I can steep the coffee for a lot longer...Cool product though...still may get one..

@artturivehmer3636 Жыл бұрын

Hei mulla on tommonen samanlainen vahvistin, jossa ei toimi output kaappeihin. Olisitko kiinnostunut ostamaan sen? Tästä videosta innostuneena kokeilin avata ja etsiä vikaa, mutta eihän siitä mitään tullut… hyvä video kuitenkin!

@AnglicanNew Жыл бұрын

So how is the coffee quality? It is gritty?

@GrumpytechieNet Жыл бұрын

Surprisingly smooth, a bit less gritty than French press.

@davidraymer397 Жыл бұрын

Is it heavy? Is it class D?

@GrumpytechieNet Жыл бұрын

It's quite the beast, 15 kg maybe. It's a push-pull off memory serves.

@radellaf Жыл бұрын

Aaaand... that's why I'd rather see instructions for just using a blade. Those strippers are so fiddly.

@GrumpytechieNet Жыл бұрын

Yupp, they work if you need to make 20 cables in one go, and you never change brand of cable. For one-off cables I generally use a razor.

@radellaf Жыл бұрын

@@GrumpytechieNet Good point. I can't say I've ever tried tweaking them for reliable cuts on one roll of cable. Wasn't even clear, or possible, to adjust the couple I have tried. Good to know if I ever have to, though.

@GrumpytechieNet Жыл бұрын

@@radellaf Almost every coax stripper I've used have little set screws for adjusting the blades, as the tolerances are so small that just switching brand of cable can make it cut too deep or too shallow.

@ZombieBath Жыл бұрын

Thanks for the video. So... I made a big mistake, I connected my pf350 (with the voltage switch on 127v) in a 250v side of an external transformer. The transformer burned in quickly, and expelled lots of smoke. I was surprised because on a visual inspection I didn't see anything blown inside the amp, just the fuse. I guess it is dangerous tocause more harm if I change the fuse and try to turn it on, so I will take it to the a professional. What puzzles me is why did the external transformer catch fire and the amp did not show, at least visualy, anything burned. The transformer was correctly connected to the 127v wall plug, the amp was switched to receive 127v and the transformer was sending it 220v.

@GrumpytechieNet Жыл бұрын

Since these amps have a switch-mode power supply internally, they can behave a bit weird, in an upcoming video I have a PF500 that did start even though one of the output mosfets were completely burned.

@ZombieBath Жыл бұрын

@@GrumpytechieNet the tech said the power section will have to be repaired, so I will have to spend some cash. Well, at least it can be repaired.

@GrumpytechieNet Жыл бұрын

@@ZombieBath They are quite sturdily built, so I'd expect only a few components being burned. It's hard to say though, repairs like that are usually a matter of replacing failed components, see if it works, finding more components to replace etc. So it can take some time to fix.

@motrix63 Жыл бұрын

I have this same amp. When I turn it on, the fuse on the back of the power plug blows after a second. Do you think it's a capacitor or mosfet problem?

@GrumpytechieNet Жыл бұрын

Could be either or a shorted power transformer. Start checking resistance between power and ground, working from the power cable towards the mosfets. That way you work towards the short. Remember to also flick the power switch on and off to see if the problem is before or after the switch. How large is the fuse in the plug, 13A?

@motrix63 Жыл бұрын

@@GrumpytechieNet Thanks for the reply. The transformer is ok because I tested it disconnected from the circuit and the fuse doesn't blow. The fuse is 1.6A as indicated on the back. I'll try to check the rest of the circuit over the weekend.

@cranegantry868 Жыл бұрын

Looks ok to do. I have lots of crimping tools here, so I'm sure one will fit.

@zaydraco Жыл бұрын

How much coffee and water is needed? Is there any grind method?

@GrumpytechieNet Жыл бұрын

From what I remember I went with the formula 60g/1000g water. French press grind is approx what you want for it.

@R50_J0 Жыл бұрын

Can't see shit. What was the point of making the video?

@rm2kmidi Жыл бұрын

I have the classic stand-type over burner siphon pot and it makes great coffee, but I like how this one shuts the burner off on its own. Aside from having to use fuel in the burner, I find most of these siphon pots are really fragile. Kitchenaid makes a decent electric Siphon Pot which I also have and actually use. The stand one just sits on the shelf.

@eddiegarcia3202 Жыл бұрын

I have this same amp. TIP31C and TIP32C run quite hot. I adjusted the voltage to 20.9 and fabricated two GIANT heat sinks for them. The last time I replaced them, before replacing the heat sinks, it lasted 6 months, then TIP31C shorted out. Collector voltage is 57VDC. Do you think the new heatsinks will allow them to last longer? I drive this amp pretty hard, but I don't want to have to replace the transistors every 6 months!

@GrumpytechieNet Жыл бұрын

Seems a bit odd to be honest, so they get hot with the amp just sitting idling, turned on with no input signal? The bent aluminium plate that function as a heat sink for the transistors is supposed to be bolted to the chassis with thermal compound in between it and the chassis. Maybe the old compound had dried up over the years?

@eddiegarcia3202 Жыл бұрын

@@GrumpytechieNet Thanks for the quick response. Idling, there is a little heat. Pushed hard, they heat up. I believe they are rated at 150C. TIP31C and TIP32C have their own, individual L-shaped heat sinks, mounted on the PCB. I cleaned off all the old compound and liberally applied new throughout. R12, R13, R30 and R31 also run hot. I've played it now for a week and so far, it's working. I'm thinking maybe it's normal. Hopefully, the larger heat sinks will give it longevity. Maybe that's why they don't make this model anymore.

@GrumpytechieNet Жыл бұрын

@@eddiegarcia3202 I'll check the heat levels in mine, I'm still in the middle of replacing some pots!

@eddiegarcia3202 Жыл бұрын

@@GrumpytechieNet Thank you. Great channel, BTW!

@eddiegarcia3202 Жыл бұрын

@@GrumpytechieNet Did you ever check the heat levels on the transistors? So far the larger heat sinks on mine seem to be working. The heat sinks are hotter to the touch than the transistors themselves!

@realtacobell 2 жыл бұрын

Can this be poured into an Alginate cast without issues?

@GrumpytechieNet 2 жыл бұрын

I would imagine that alginate can't take the temperature.

@germanjohn5626 2 жыл бұрын

Lucky its an old video, and not very good since static tests on a cable doesn't really tell you anything. , these days for 50 bucks one can get a NanoVNA and do meaningful testing of cables.

@GrumpytechieNet 2 жыл бұрын

You're quite right, but I'd still recommend a resistance test as it tells you if you accidentally shorted the cable making it, and if you have a DC-shorted antenna at the other end of a longer cable it also tells you of you have excessive resistance. VNAs are superior, but you might not always have one with you.

@richardshort4587 2 жыл бұрын

Great video. Are you planning on making a video showing how to make this set up and what components you used and schematics. Thanks.

@GrumpytechieNet 2 жыл бұрын

Check the link in the description, he has a series on how to build it and explains how it works. Essentially it's just light bulbs in parallel with each other in series with the load. Each bulb has a switch in series with it, and the bypass is just a switch without a bulb in parallel.

@richardshort4587 2 жыл бұрын

@@GrumpytechieNet Thanks 👍

@daviddiaz8520 2 жыл бұрын

Me gusto mucho que tu video no este editado y sea realista, realmente se puede aprender con un video así, porque demuestra las complicaciones reales que se pueden tener en estos trabajos, algo que no se ve cuando un video esta editado y todo parece ser tan sencillo y "mágico", saludos y agradecimientos desde Córdoba, Argentina.

@LexLuthor1234 2 жыл бұрын

very nice, the patina of the brewer, and especially the copper and faded gold is beautiful. Imo it is more beautiful this way, than if it was a shiny brass and gold version. But each to their own of course :)

@seanf42 2 жыл бұрын

Hi, thanks for putting up this video, I have the exact same amp, with the same problems, hum and scratchy pots. I'm not an electronics expert but have done a fair bit of tinkering so will replace the caps and clean the pots, where would you recommend sourcing the components, RS? Thanks Sean

@GrumpytechieNet 2 жыл бұрын

No worries mate! The components are from Mouser, they have quite a good policy regarding free shipping including import duties. I'm actually working on a third part on this video, as the pots never cleaned up properly, so I'd get the pots as well while you're in there.

@seanf42 2 жыл бұрын

@@GrumpytechieNet thanks for that I'll look out for your next video. I'm also missing 2 knobs, no idea where to get them from!

@seanf42 2 жыл бұрын

@@GrumpytechieNet Further from my previous comment, my amp was water damaged so much that it had rusted the bolts holding the board to the cabinet so couldnt get it out, another one came up on ebay for £50 so I've bought that one, seems perfect apart from a crackly volume pot, as it's over 20 years old would you recommend replacing the caps as a matter of course? And as a thank you for this video I have 3 knobs which you can have, if you can send me your email address I'll contact you and post them to you. Thanks Sean

@GrumpytechieNet 2 жыл бұрын

@@seanf42 I'd say replace them all while you're at it, they aren't that many nor very expensive. Be prepared that some of the pots might be shot as well, I had to replace the volume 1 Meg as well.