DigiTech GSP-21 Repair (Battery replacement + Power supply fix)
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- Опубликовано: 26 июл 2020
- I bought an old rack mount effects unit from Digitech called the GSP-21. Initially, I thought it only needed a battery and while creating a video showing replacement of the battery I discovered there was a power supply problem causing a faulty memory. I got everything working now. Fun little unit.
1:41 - Battery Diagnosis
2:27 - Battery Replacement
3:14 - Testing New Battery
4:21 - EPROM / Firmware
4:59 - Photo of EPROM chip version 1.1u
5:15 - PCB tour / inspection
5:33 - Analog Equalizer Circuits
5:57 - OP Amp Datasheet
9:02 - Discovery of the Power Supply Problem
9:41 - Unit dead - troubleshooting
12:50 - Troubleshooting / measuring voltage across capacitor
13:36 - Found a bad connection in power supply
15:50 - Found cracked trace beneath PCB
17:01 - Power supply fix
18:38 - Testing unit
21:07 - Me Playing Music
Got a V1 with the Legend upgrade chip maybe 10 years ago or more. Was excited at it was in all of the 90's guitar rags as the best-thing. Well, the 80/90's cleans are its strength but the gain tones are some of the worst committed to a DSP.
For maintenance, the lower main PCB which is common to many Digitech/DOD units of the era, has a few Tantalum coupling caps. These fail to a short eventually and let out a pile of smoke. Took out other parts, don't let it happen. One torched so badly in mine, it damaged the board right next to the PCM54 DAC and sucked to fix. Replace them with Electrolytics. If the meters max out, there is a big low-pitched noise, and the acrid smoke, it's those Tant caps.
Don't let the battery leak either. Change it regularly. I just use a 3xAAA holder and put it in place.
I seen it in a 1989 at a guitar clinic to promote. Someone won it. It was pretty ground breaking. Affordable rack for that time. The clinician had some tasty fusion chops had a volume pedal and he looked in an old digitech distortion pedal. And did well with. The pros came out later and I got the pro used in 91 for 450. And never bought any pedals up until the 2000s. Think legends were in 92 and then they stopped. It was easy to program. And the pedal board could easily have patches where you could turn off and on delay and modulation effects. Go from distortion and clean on one patch. Move to the next patch. I liked that part better than the 2101. And the display was better than the 2101
My first unit was a GSP 2.1 Legend
super useful, thnks
Hi, I recently bought a GSP21 Pro, but when I turn on the unit then the Overflow led appears and I cant ear the sound of the preamp, even the input level can stay low and still indicated overflow.
The electronics work great my expression pedal needs a new Switch and my foot pedals need some work
I gotta a 2101 studio been the fritz for a year. Display would just randomly shut off along with all audio but the tubes would still be lite. It would come back on sometimes it would do this several times then be fine. Seemed like if it sat for awhile it would get bad. Recently it wont turn on at all but tubes are lite. Thinking it cant be power cord or tubes wouldnt get power. Anyone got any ideas?
Does anyone know where I can buy a compatible power supply for my vx400 digitech? Not from digitech
Hello, mine is a pro version as your but it produces a weak output. I really dont find what is wrong. I have a legend version and i was able to swap components in last chance. Circuitry are quite differents if you compare both schematic at page 4/7 (legend and pro). Im losing signal around DBX2150 but this one is good. Really annoying failure.
I think you can buy these for about $200. But, yes, I agree - some repairs suck you in and you can't stop.
That’s when I bought it . It’s my old 21 lol
Trivia - this unit was used a
On bulk of tracks on the Coverdale Page LP
Cool!
Saya punya efek ini tp sekarang eror?? bisa bantu perbaikannya
I need some one I need some one to repair my RP355 any recommendations
Aside from taking my guitars to Gryphon Stringed Instruments - I don't have any recommendations. Generally, consumer electronics aren't worth repairing since replacement is often cheaper than paying someone to repair the original device.
I have a gsp 5 I haven't used in 8 years. I put a new battery in and the batt light is still on and will not save new settings. Ay ideas.....Thanks Mike
I bought this one off of Reverb - and it was listed as working. At first I thought it was just a dead battery - but it turned out to be a bad solder joint. I got lucky fixing it.
@@silvermica Thank you
Please, any idea what u21 is? It's missing on mine. Part number Please?
I've ordered a new chip for this unit - when I pop it open I'll have look at U21. Which board is it on? I probably will not completely disassemble - so if U21 is under a PCB I won't be able to see it.
17:25 My unit needs new battery but I dont have original one to match it up What kind of battery is it I know its 4.5V but how many mAh ?
Mine has Energizer No.523 4.5V or buy 3 x 1.5 v and a housing , there is plenty space for it behind the power switch.
I bought the battery off of Amazon. Here are the details: Exell Battery A21PX 4.5-Volt
Hi
anybody work or have a DIGITECH twin tube GFX-1 ?
i Have a burnt U9(voltage regulator?) in my unit.
i can't read the number from the element..and there is no schematics
Can anyone help me on this one?
I'd guess any +9volt regulator would work. I replaced a 3 in my 2112.