How to Fix Blackstar HD100 Series 1 Intermittent OD1

Very nasty intermittent problem where OD1 kept dropping out. I got DEAD luck with the fix!

[@tjsogmc]

Good job on the fix! I refuse to work on Blackstar as a general rule, and if I do, then it's just a cursory inspection for something obvious like disconnected wires or whatever. Even though I can work on the boards, I won't. It's too much work for too little payoff.

[@stuartukguitarampguy5830]

That's pretty much how I feel. I'll usually have a ;quick look' just in case it's fixable.

[@brettwalmsley3434]

Wow! I am the first? Great show, great show as always! Keep posting! Cheers from Germany - Brett

[@stuartukguitarampguy5830]

Thanks Brett!

[@coltronex]

Good job Stuart,keep the repair productions coming,really enjoy them,keep well,regards Colin.

[@stuartukguitarampguy5830]

Thanks Colin.

[@montygore1200]

Hi Stuart. Glad to see you again. Good eye on that repair. It could have been a night mare. Way to go!!!

[@stuartukguitarampguy5830]

Thanks Monty. I try to do a video about once a fortnight.

[@ralphj4012]

Well diagnosed. The large heatsink (& mosfets ?) looks to be power supply related. Switch-mode in an audio amp, sacrilege

[@stuartukguitarampguy5830]

I suupose it COULD be but it looked for all the world like a typical 50W/100W FET transistor amp. That huge heatsink also wouldn't be right for a switchmode.

[@ralphj4012]

@@stuartukguitarampguy5830 Agree, very odd. As you say, that amp already contains output valves. Maybe the heatsink and FETs is an attempt at an analogue PSU (pure guesswork on my part), then maybe it needs to be partly aplauded

[@stuartukguitarampguy5830]

@@ralphj4012 Yes odd. I can find almost nothing online about the HD100. If you find anything let me know thanks.

[@fiddlix]

Blackstars all seem to have these issues with the circuit board interconnects. A brilliant repair to an unrepairable amp..!

[@stuartukguitarampguy5830]

Thanks David. Amazing that the designers let this pass really. Don;t they know???

[@fiddlix]

@@stuartukguitarampguy5830 as long as these amps make it past the warranty period, I really don’t think they care.

[@jothanankrogh]

Just a note: I recently repaired a 50w Blackstar where one of the electrolytic capacitors in its auto biasing circuit had failed, causing one el34 to turn completely red, and blow the mains fuse. The prob seemed not to be an underrated capacitor, but just low quality. Blackstar was completely uncooperative when I emailed them explaining the situation and asked for a schematic.

[@stuartukguitarampguy5830]

Thanks Jonathan, nice fix well done. I always think it's totally stupid holding out on schematics. Gives your company a really bad reputation.

[@edwardhannigan6324]

Hey Stuart...Lucky one there..! Nice fix and info, bit of a nightmare those amps..Ed..UK..😊

[@stuartukguitarampguy5830]

Yes relieved to have found it so easily!

[@pda49184]

Well spotted Stuart.. Like you, I dislike these 'throw-away' modern electronics. Hardly a friend of 'net zero' , but companies that produce this stuff are hardly ever get called out on their future landfill products. Still being a gigging player I'll always look for the more conventional amps even if there is a PCB (like most of the Fenders etc), but are relatively easy to diagnose and fix.

[@stuartukguitarampguy5830]

Hi Pete I think it's simply cost. The cheaper they can make them, the cheaper they can sell them and the more they will sell.

[@danielsaturnino5715]

Brilliant. Not the amp ofc, your work :)

[@stuartukguitarampguy5830]

Thanks Daniel!

[@richwallace6854]

I'm not there to see , but could have soldered the joint wheve the pin is crimped to the wire?

[@santiagomoreno696]

I though that Blackstar would also have SMD components like the HT series. Love your videos.

[@stuartukguitarampguy5830]

Most of the later ones do. Interestignly I just had an HT5 in with through hole components. Must have been an early one, All the later ones have SMD. AND Blackstar have stopped selling replacement boards for these amps. Great!

[@tomfoolery2082]

I had a 20 watt combo which did sound pretty good , but it died 3 weeks after the warranty was out . Blackstar was no help . Said warranty was out if I wanted them to fix it send it to them and no way would they send a schematic . 2 tech's here said it wld cost more to fix than buy a new 1 . The warranty was out I took a chance my loss .The chassis is at the bottom of my pond as a boat anchor . I'm not a fan .

[@goodun2974]

Check out the Psionic Audio audio channel; he has worked on several Blackstars and doesn't have much good to say about them.

[@stuartukguitarampguy5830]

@@goodun2974 I endorse this comment. Psionic are very good.

[@stuartukguitarampguy5830]

Ha ha! I like to think you aren't joking!

[@tomfoolery2082]

If ur talking to me , no I'm not joking , tied on a short piece of rope , swung for all I was worth . Now is sleeping with the fish's . I kept n use the spkr n cab . Liking ur channel .

[@stuartukguitarampguy5830]

@@tomfoolery2082 Ha ha, nice one. Remind me not to get on the wrong side of you... :)

[@11000038]

Well done on the repair. I have a couple of valve Black Star amps so I hope they stay ok. Have you a favourite brand or model? Thanks for the video!

[@stuartukguitarampguy5830]

Hi Tim yes they are good whilst they work but not easy to fix if they go wrong. I have a soft spot for the Fender Blues Junior!

[@sjgreaves]

I dunno, Black star started so well with the Artisan amps, all point to point hand wired, really quite beautiful inside, but I suppose the desire for complexity at an affordable price lead to machine made PCBs... I have an Artisan 15 which is a great amp but I would be reluctant to buy a more recent Black star even though they do sound great.

[@stuartukguitarampguy5830]

Yes you've summed it up perfectly.

[@suso_alonso]

The brand of amplifiers of the disciples of Jim Marshall. Too solid state for my taste. Greetings, friend Stuart.

[@stuartukguitarampguy5830]

Agreed Suso!

[@merkabah2]

@@stuartukguitarampguy5830 Hey Stu which amps in your oppinion do you prefer? or like to work on ? cheers mate :)

[@stuartukguitarampguy5830]

@@merkabah2 Hi I have no preference for amos to play because I am not a guitarist. To work on, any old valve amp because they are straightforward. Worst amp to work on? Fender Bassbreaker 15.

[@merkabah2]

@@stuartukguitarampguy5830 thank you kindly

[@dave-d]

Thanks for the wire stripping tip. I've been wrestling with the wire strippers for years! Got a Blackstar with an intermittent rotary encoder dial here. Board out. Boo. Have fun. Thank you.

[@stuartukguitarampguy5830]

Great!

[@greetingz2all]

hope to see a good vid soon Stuart

[@stuartukguitarampguy5830]

Yes been on hol so should crank one out soon!

[@nogbadthebad2609]

Great job. I totally agree Stuart, Blackstar are far too complex, with a flimsy mix of boards, chips and thin connectors which all = unreliable. I'll never buy another Blackstar.

[@stuartukguitarampguy5830]

Yes agreed. Shame though as they actually sound quite good,.

[@ferraridinoman]

Nice one young Stuart! Bloody awful amp just waiting to go wrong!! (Bloody circus boards/computers etc etc!) just like on modern cars! when they go wrong NOBODY can fix 'em!!

[@stuartukguitarampguy5830]

Not may favourite amps to be honest!

[@chickenlickin3820]

just junk : ( well done on the fix : )

[@PhuketMyMac]

Blackstar might sound good but there are designed as piece of crap as everyone could see. Not the first time I see a video on a tech warning about those unreliable design. Happy to see more and more people warning buyers that Blackstar amps are just not made to last, but instead made to be replaced like typical consumer electronic. Sad to say the least...

[@stuartukguitarampguy5830]

Yes it's a bit sad really.

[@gingercat777]

Not enough knobs!!....lol

[@stuartukguitarampguy5830]

I'm sure they could have squeezed a few more in!

[@donciseau]

Excellent video sir!

[@Dutchamp]

Dislike these connectors had a problem with a cd player at the connector same problems. Cut them all and solder them all to there connection pins

[@stuartukguitarampguy5830]

Yes sadly there are 150 in this amp so I'd still be doing them now! :)

[@tonedriverss8629]

Blackstar = horrid . The customer is very lucky you even took it in ! Worst piece of garbage ever . They should be banned !

[@stuartukguitarampguy5830]

Yes I'm starting to feel that way muself about Blackstar. They've just discontinued supplying spare boards for the HT1 and HT5 which means literally THOUSANDS of these amps are now heading for landfill when they fail.

[@miguelrichartmellado2834]

no subtitles? fuck youtube.

[@stuartukguitarampguy5830]

Didnlt they come up? I thought that was automatic?

[@miguelrichartmellado2834]

@@stuartukguitarampguy5830 l like your channel, but I cant say the same for youtube. Thank you.

[@el_micha]

​@@stuartukguitarampguy5830 @miguel richart mellado - watched the video today. I got the automatic English subtitles. Maybe it takes a while for the software to generate them? Don’t know how they make it work.

[@stuartukguitarampguy5830]

@@el_micha Me neither!

[@goodun2974]

#@&*! sake, Stuart, a plug-in connector is the very last place that you should ever be using Deoxit! That type of cleaner should only be used on contacts that are frequently moved or adjusted so that the contacts will wipe themselves clean. The lubricants and residues will soak into the wires where they are crimped to the little connectors inside the plastic block, and it will cause intermittent problems later on. Use pure alcohol only on this type of connector. I mean, really , FFS !!!

[@stuartukguitarampguy5830]

Can't agree with you on this one I'm afraid. This is part of the Deoxit myth which I've been trying to bust in various vidos.

[@goodun2974]

@@stuartukguitarampguy5830 , I have cleaned literally thousands of those exact same style of plugin connectors in the last 15 years of working on (mostly) solid state hifi and audio-video equipment. Unplug them, spray them with alcohol, and plug them back together a couple of times to wipe them clean. No residue is ever left behind. In extreme cases I'll clean the male pins with a shaped/shaved-down pencil eraser. I have actually recrimped those terminals from time to time and sometimes even replaced the terminal with a freshly crimped one (we have the correct tool and matching contact pins at the shop). The main problem that can occur if you leave a residue behind inside one of those connectors is that the crimps to the wires are not crimped tightly enough to be gas or liquid tight (and the stranded wires have a capillary effect, so they will suck the cleaning solution up into the wire). Adding oily residue to the crimped part of the connection will not improve the connection, it can only make it worse. Also, you don't know what passes through that entire plug-in connector, but almost certainly it will have both DC voltages and audio signal. It might even have AC voltage passing through it to heat a preamp tube or a florescent display. You're gonna do what you want, I know ---- but it's bad technique.

[@stuartukguitarampguy5830]

@@goodun2974 Thanks for that, useful info. As you can imagine in 50+ years of both high level design and untold thousands of hours of repair, I've cleaned a few tens of thousands myself with literally zero problems! I'm not denying alcohol works (and I do use that also) but I'm on a mini mission to debunk the negative info around (e.g.) DeOxit. Your claim amounts to 'DeOxit damages these connectors'. I've already debunked the "DeOxit dissolves carbon tracks" myth which is rife on the Internet. I do not believe that DeOxit causes the issues you claim. I'm open to convincing but I'd need proper experimental proof. DeOxit doesn't 'disolve' or 'attack' anything, it's also hundreds of megohms resistance so I'd also need a credible mechanism for the problems you claim. It's not a hill I will die on, but it's you who are coming in with FFS and so on, so it's you who must back up your claims with proof.

[@goodun2974]

@@stuartukguitarampguy5830 , think about this logically: switches and pots usually contain factory lubrication, so there is some precedent for using a lubricating cleaner on them (whether factory lubes and Deoxit residue are chemically similar or compatible is a separate issue); but have you ever seen a case where these plug-in connectors were treated or coated with any type of residue-leaving cleaner or protectant by whoever manufactured the PC board or the electronic device? The only time I ever see them containing any kind of residue is if some tech or the equipment owner has obviously been inside the unit and added it to the connectors. Also, when component-stuffed circuit boards are cleaned, manufacturers invariably clean the boards and the attached parts with either isopropyl alcohol or, in the case of more recent devices made with lead free solder, distilled/deionized water. ( I just read a long article by GC Electronics about this). They don't spray them with Deoxit or any type of residue-leaving cleaner! Anyway, since you already said that you know alcohol will clean connectors, why would you use Deoxit for that same purpose when it costs at least ten times as much as alcohol does? Also, since your own tests indicate that the conductivity of Deoxit is in the megohm range, that qualifies it as an insulator; while a thin insulating film might be okay on a moving contact that displaces the insulating film when the switch or pot is operated in normal everyday use, the contacts on these plugins are stationary for years at a time. PS, those connectors are often cold-soldered at the factory, even on older equipment made with leaded solder; your "dry" joints are a common occurence with these. I've routinely resoldered I don't know how many of the damn things; thousands, for sure. If the solder joints aren't already loose, they will often become so after you unplug and reseat the connectors in order to wipe oxidation off of the pins.

[@stuartukguitarampguy5830]

@@goodun2974 Hello again. A couple of thigs. Firstly I've consistently found alcohol to be less effective than DeOxit on pots. In some cases alcohol hasn't cured the scratchiness at all, DeOxit cures it instantly. Other times the alcohol seems to work, so I default to DeOxit. On the multi connectors, no of course factories don;t spray these connectors with DeOxit (or whatever). Why would they? The connectors are all new. Surely we're only discussing slightly tarnished/dirty connectors here? I'm not saying alcohol doesn't work or to try and persuade you to use DeOxit. My sole interest here is to correct (in my opinion) the constant stream of misinformation about DeOxit. The prevailing myths are that it eats this or that, dissolves the other and so on. This is simply not true. Now I'm suspicious about the 'leaves a conductive residue' idea. Is this true or just aother myth? I could think of a test. Get a connector plug and socket with a 10-way ribbon. Socket soldered to a boad but tracks go nowhere. Test the insulation between adjacent pairs of wires at 500V. Assume it's open circuit. Soak with DeOxit and check again when still wet. Check again when dry. Try 10-20 applications allowing it to dry each time. Check again. Any leakage? You're correct in your conductive residue theory. Still open circuit? - Well, you can never prove a negative to let's just say I'd be dubious about your claim! It's ONLY DeOxit I'm interested in here. Lord alone knows what other people had sprayed on those connctors you've seen.