Kurzweil K2500RS Synth / Sampler Overview, Upgrades, and Repair

Part 5 of the series on the Kurzweil K2000R and K2500R production workstation / samplers. I briefly go through the K2500RS, discuss issues, problems, upgrades, and other options for it.
Build yourself K2500R PRAM Module: github.com/dojoe/K2500-PRAM
Kurzweil K2500R Resources: kurzweil.com/k2500r/
K2000R / K2500R Series:
Part 1: • Kurzweil K2000R and K2...
Part 2: • Kurzweil K2000R K2500R...
Part 3: • Kurzweil K2000R - Part...
Part 4: • Kurzweil K2000R - Part...

[@rickboring7165]

Thanks Brad! I greatly appreciate your videos and the thoroughness. Those little details sometimes are great lifesavers.

[@janntucek]

Awesome Brad! Thank you so much for these repair & information videos. If you are going to do another Bench Notes episode it would be great to see your recommendations on tools, equipment and information for getting started repairing audio gear.

[@matrix12x]

super thorough video!! I always look forward to these videos

[@EvLoutonian]

Thanks for this awesome overview!

[@wojtekniewiadomski9451]

Yay! New video from bradthx!

[@RabbitintheMoon]

I have the kdfx board.. love this tutorial,, thank you

[@EntropyCoM]

Hey bradthx! Thanks for the great videos. I upgraded my studio-park with a K2500RS with all ROMs in. But apart from my K200R V3 with Sample-Board in the insert-cable connection to my patch-bay didn't work on the left channel for A. And I wondered why (on my K2000R it worked like charm). So I opened my K2.5 and wondered to see that the transistor Q1 on the connector board is missing. Obviously, something the previous owner didn't mention when selling it on ebay. Additionally, the capacitors C09 and C10 (1000pF) were cut through or simply damaged, i dunno. Maybe for better signal quality. The transistor is no problem, it is a simple J109 Type (costs about 0.35 Euro/ct a piece), but with the capacitors I am realy unsure and do not know what type those were. I've seen that the two diodes D4 and D5 had been replaced additionally. Maybe you know what type of capacitor I can buy or give me some advice for replacement. Those are no elcos I suppose, more of a ceramic type but radial - well I don't really know. Only that they must be bipolar I think and have 1000pF. Do you have any idea? Best wishes

[@andrewverran3498]

Sold my k2500rs in 2000....heaps hard to find in Australia....ps..i also into cb radio (ssb) and a few ham rigs. Love your knowledge Peace

[@mrz80]

"bought it... can't for he life of me find it...." I know THAT feeling! Number of times I've double-bought stuff that I'd misplaced in that mess out in the garage... :P

[@sagamusix]

Hope to see the P/RAM in the next video :) Regarding OS versions: To the best of my knowledge, 3.02 is the latest OS version for units without KDFX - at least it's the latest available on the Kurzweil website. 3.5(0) would be the version number of the object ROM that goes with OS version 2.80. 3.90 is the latest object ROM version. Interestingly on my unit, I have an issue with any OS version later than 2.80 that not even Kurzweil could explain. With certain filter modulations, I get an audible click on all later OS versions (e.g. audible in patch 891 Space Station), so I'm staying on 2.80 with my K2500. Apparently noone else has this issue. My K2500 had some battery damage at the bottom of the case but I cannot quite imagine how that would affect 1) only specific filter modulations, on 2) certain OS versions only. If some chip was damaged, the results surely would be more "random".

[@maxproskauer9272]

new vid yesss!

[@ShallRemainUnknown]

The K2500 and K2600 units use CFL backlight bulbs which last a long time. People have converted the backlights successfully to LED using LED strips removed from broken tablet computers.

[@kenhamilton2392]

Hi Brad, fantastic video series on Kurzweils . For the K2000R is it possible to find a new, drop in replacement for the transformer?

[@marcduchesne906]

Hi Brad, congratulation for your very informative channel. I purchased a 2500RS from eBay. It needs a faceplate and couple missing buttons at front. Any source for these ?

[@dimsump6049]

great video - the only thing I couldn't find was how to replace the battery (for PRAM) - is it in here somewhere?

[@snappibank]

Great content.I have the K2500S and I would like to update RAM chips. Is there anyone who knows the exact chips to look for?

[@mindgalleryvoodoo5266]

Hi Brad, thanks for great videos on the K2000R, much appreciated. I hoped that you would cover the error I have but I did not see it. So maybe you can point me in a direction to solve it please. When I turn on my K2000R it shows vast animation and firmware, but then it goes on displaying "Waiting for keyscanner" and then the screen is blank with a faint "Waiting for keyscanner" . I've changed all 28 caps on the boards, so they should be good, measured around the board and got the 12V and 5V readings as expected from the service manual, do you or anyone else have an idea what the problem could be or what I can try next? Unable to do any kind of reset, power and 1,2,3 or power and +/-,0,CLR by the way, it seems to be stuck in a "Waiting for keyscanner" boot loop.

[@GrandpaShreds]

Hi Brad, hoping you could help me. I have a Lexicon MPX-1 in which none of the displays light up except for the main display which only the back light lights up, no characters. I've checked voltages everywhere and they seem to be there. I've passed a 1Hz signal and the input pot works, but no output. I'm a complete novice and don't where else to check or what to do. Do you have any ideas? Thank you for your inspiration.

[@dlichtenberg]

have you made any electronic albums? or have a site to listen to your music?

[@Masoic21]

Hey Man Do you have any experience with a Ksp8? I’ve had one for years that needs repair, the analog outputs don’t work.

[@jeffevansmusic]

I have got a Kurzweil K2500R and it has a faulty LCD display. I am trying to get a LED replacement. The connector though has a long 20 pin in line type arrangement. Do you know where I can get a replacement LED display unit from. I have already built the platform for the slightly smaller/thinner LED displays.

[@musicproducerberlin2024]

I have a 2500R where the F/I switch always releases. I Suspect an error current, but i cannot measure this. Do you have a suggestion what the cause could be ?

[@Kraatzman]

Thank Brad Have a rather lengthly question. I bought a k2500x In good condition, I added 128mb Sample 30-pin RAM, and tried to build the PRAM board that is out there on the internet. Something went wrong and I bluescreened the unit. I bought a Second k2500xs on ebay (sampler module was unknown at the time) had all the innards removed except the keyboard to try to build one unit out of two. This new unit is a uses 72-pin Sample RAM. I am trying to isolate the bad board and replace with a newer board. 1. Knowing I blew the first unit with PRAM, what boards were affected in the first unit, 2500x. 2. Can i interchange these boards at all between the A-J Model and the K model? 3. This second unit may also be a bluescreen of Death. What board would be affected for that? 4. Any last suggestions. Thanks for any help.

[@DjIdea]

hey brad how can I get in touch with you? I have a few questions and would like to get on a call. im need to the k2500 world but I want to max this thing out

[@Will-hr1qq]

I just got one of these with sampling feature, sounds great. only issue is when I sample something and play the sample back alongside the onboard instruments in song mode, The sounds intermittently clash into sounds a horrible glitching noise, it tends to happen when sending multiple sounds through the 8 outputs. Onboard instruments play fine together through outputs, any idea what would cause this? Also occurs when loading samples from a k2000 disk

[@ShallRemainUnknown]

Ask on forum at forums.godlike.com.au/ Also, there are Facebook Kurzweil groups, you could ask there.

[@Will-hr1qq]

@@ShallRemainUnknown thanks, appreciate it

[@Sonoman3k]

Hi Brad. Sorry to write you in the comments of this video, but I would like to know how to contact you to send some images of the failure of my Alesis Fusion. It is a failure to start, the synthesizer hangs, only blue background screen and many of the yellow LEDs of the buttons on and does not respond to anything. I bought the keyboard new in 2006 and the failure occurred in 2010. I am from Venezuela and I think I must be the only person who has this synthesizer here, therefore there is no technical support. If you can give me any information, I appreciate it.

[@timothypnolan]

Hello. Do you know if it's possible to convert a k2500r to a k2500rs? like my machine has the space for the inputs etc

[@Ez-qt7dx]

Yes, if you can find the Sampling Option SMP-2

[@huhummmmmmm]

mine has a blue screen of death :(

[@jktakaowen5331]

I have Kurzweil K2500RS OS v3.02. When you select a SCSI source in the "Disk" section, the device freezes. It helps only reboot and reset the settings. All capacitors are replaced with new ones. What could be the problem?

[@jktakaowen5331]

I noticed that the SCSI Bus Controller L52C80JC 2 was soldered.

[@ShallRemainUnknown]

The keyboard and rack units use different sampler boards, not interchangeable. In addition, I believe there is different revision sampler board that was sold for K2500- through K2600-series from 1995 when the K2500 debuted, and that version will not work with the K2000. The K2500 should work with either revision sampler board (but again, keyboard and rack board differs).

[@_oscillator]

I have sampling board on my K2VX and many years ago I used it a lot, but now this board is totally outdated. It's much easier to do sampling and sample editing on a computer, where you can see both channels in same time on big screen, do zooming and zero-crossing with mouse etc. After editing, you can simply load the sample into Kurzweil via the SCSI port, so sampling board is not necessary at all.

[@ShallRemainUnknown]

@@_oscillator Yes, many people (most, these days?) conduct sampling and basic sample editing/processing on computer and then dump to K2-series for synth engine. If you can't use your sampling board in K2500 down the road (keyboard version, in which I believe it's compatible) for "LIVE MODE" audio input, then suggest selling the board to fund a SY/TG-77/99 like we've messaged about previously! I'd love to hear what you could do with a fabulous AFM synth!

[@_oscillator]

​@@ShallRemainUnknown Yes, my first synth was DX21, more than 30 years ago. I'm still thinking about TG-77, but I stopped to expand my rig, because I already have 7 synths. That means VAST of my K2VX, Z-Plane of Morpheus and UltraProteus, additive synthesis of Kawai K5000, transwaves of MR Rack, vector and wavesequencing of Wavestation and VA of Blofeld. That's enough for me. I would like to have also the TG-77 (or even better, SF1R), JD-990, Fizmo, Neuron, Iridium and Nord G2, but I'm over 50 and just don't have so much time left to learn them all. Every synth needs at least few years to know it perfectly. So... that's a reality.

[@ShallRemainUnknown]

@@_oscillator Haha, I have a similar assemblage, and have come to a similar conclusion. My point was that the sampler board might have value to you, or else to others, in which case you could sell it! It seems an (A)FM synth would still expand your pallette, but, as you say, such expansion might be counter-productive to you depending on your goals. Some like to collect synths, or learn synths, or talk synths, or record synths, or compare synths, ot trade synths, or repair synths , or write instrumental music w synths , or write songs with synths, or perform w synths. Probably best for anyone to define their goals and stay focused!

[@_oscillator]

@@ShallRemainUnknown So true. My goal is to create some experimental stuff, time after time, because it's just a hobby for me. I already have some tracks on my channel, like "Darkness from Above" and "Insanity" trilogy. I'm just trying to create sounds that I haven't heard before, and I do it with a simple setup. That's it. All the best, mate, it was a pleasure to meet you here!

[@alphabeets]

Man, slow down. It’s hard to understand you. Otherwise, nice video.