Many players want to install pickups so they can use their high-end or vintage guitars for live performances—but they’ve long been concerned about enlarging the endpin hole, which could affect the instrument’s value. That concern has been around for years, and it’s still very much alive today.
あ、写真がちょっと古い・・・
Ah, this photo is a bit dated...
4極端子タイプを始めた初期のものです。
This photo shows one of the early units from when I first began producing the 4-conductor terminal type.
Around 1997, I began producing music and customizing or repairing electric guitars in Kobe under the name Curious Projects U-TAK, alongside my main job.
自宅に工房を作り、本格的に活動を始めたのが2001年。
And in 2001, I built a workshop at home and began working in earnest.
Until now, I’ve only provided the mini endpin jack to select shops or to individuals who found me through searches and reached out directly—but I’m now considering offering them for general sale.
進捗があれば、お知らせしますね。
I’ll be sure to share any updates as things progress.
さて、本題。
OVATIONのプリアンプ、Optimaのチューナーの電源が切れないという故障の修理の続きです。
Now, back to the main topic.
This is a continuation of the repair process for the OVATION preamp, Optima—specifically, the issue where the tuner won’t power off.
Last time, I suspected that the tuner’s power switch on the Slider Board, along with the TLC3702 IC that forms the one-minute auto-off timer, might be the cause of the issue—and had just ordered replacement parts.
Since it was taking time to source the TLC3702, I tried replacing the push switch in the meantime—but the available parts didn’t match the terminal layout.
The switch on the right side of the photo matches the body size and terminal pitch, but the terminal layout and push knob mounting dimensions don’t align properly.
下の写真の一番上の接続パターンが元々搭載されていたSW。
中段が購入品。
The top switch in the photo shows the original terminal layout used in the unit.
The middle one is the replacement part I purchased.
先ずは、この購入品のSWを使って、SWを交換すると症状が改善するかどうかを確認します。
First, I’ll try replacing the switch with the purchased one to see if it improves the symptoms.
I removed the TLC3702 and installed an IC socket in its place, so I can easily replace the chip again if it fails for any reason.
新しいTLC3702を取付け。
I inserted the new TLC3702 into the IC socket.
結果・・・
ちゃんと電源が入り、1分で自動OFFする様になりました！
And the result… the power now turns on properly, and the auto-off function works after one minute!
さて、機能は復活できることが分かったのですが、問題はプッシュSWの代替品。。
Now that the functionality is restored, the remaining issue is finding a suitable replacement for the push switch…
そこで、悩みに悩んだ末、一回り小さなプッシュSWを使い、端子配線を加工して配置することにします。After much deliberation, I’ve decided to use a slightly smaller push switch and modify the wiring to fit its placement.
下の写真の下側が手配した小さなSW、上が元々のSW。
In the photo below, the smaller switch I sourced is shown at the bottom, and the original one is at the top.
With this smaller switch, I can route the wiring around the terminals while keeping the overall height consistent.
And the operating rod also fits into the push knob’s mounting hole, which makes it easier to modify the knob mounting.
Let’s start with the push knob. Even if it can’t be removed, it won’t cause any issues with installation or operation.
So in the worst case, I could simply glue it in place—but since it was originally designed to be removable, I’ll look for a way to retain that feature.
詰め物をすれば取付けできるのですが、ノブを付けたり外したりすると取れてしまいます。。
At first, I considered using filler material to make the knob fit.
That does allow for installation, but the filler tends to come off whenever the knob is attached or removed…
そこで、何か樹脂や接着剤を使って整形して取付けができる様にならないか検討します。
So I considered whether I could shape something using resin or adhesive to allow for proper mounting.
最終的に目を付けたのがコンクリートボンド！
強度も高く、経年の耐久性も高い接着剤で、時間と共に硬化するタイプです。
In the end, I settled on using concrete bond!
It’s a high-strength adhesive with excellent long-term durability, and it hardens gradually over time.
これをプッシュSWの操作部の先端に塗布して成形します。
I applied it to the tip of the operating lod and shaped it to fit.
To address this, I first lay out the wiring to avoid any crossings, then fill the area with heat-resistant adhesive for insulation. Once the adhesive has dried, I proceed with the next layer of wiring.
下の①が1層目、②が2層目、③が3層目です。
In the photo below, ① indicates the first layer, ② the second, and ③ the third.
端子を折り曲げ・・・
I bent the terminals...
先ずは第1層目を配線。
I wired the first layer.
耐熱性の樹脂接着剤は、2液性のセメダインのTUFを選定。
For the heat-resistant resin adhesive, I chose Cemedine’s two-part epoxy, TUF.
Since it withstands temperatures up to 240 °C, it can tolerate the heat during soldering to the PCB.
And by increasing the heat mass, I also aim to prevent the solder joints on the switch’s tin plated wiring from melting.
2層目の接着剤の充填が固まり、3層目の配線。
Once the second layer of adhesive had cured, I proceeded with the third layer of wiring.
接着剤が固まり、スズメッキ線をカットすれば完成！
Once the adhesive has cured, cutting the tin plated wires to the specified length completes the job!
基板に取付けると、高さもちょうど良い感じです。
Once mounted on the PCB, the switch height felt just right.
機能をチェックして問題無かったため、TLC3702もICソケットを取り外し、基板にハンダ付け。
After confirming that everything functioned correctly, I removed the IC socket and soldered the TLC3702 directly onto the PCB.
ICソケットがあると高さが高くなり、ケースに収まりません。
For reference, using an IC socket increases the overall height, making it impossible to fit inside the enclosure.
延長したControl Boardのフラットケーブルを取り外し、元通りにケースに組み戻し。
I removed the extended flat cable from the control board and reassembled everything back into the case.
これでプリアンプ本体の修理は完了です。
With that, the preamp body repair was complete.
さて、チューニングメーターはと言うと・・・
専用のICが故障しているため、修理できませんでした。。
As for the tuning meter... unfortunately, the dedicated IC was faulty, so I wasn’t able to repair it.
これは、何かチューニングメーターの代替品を考えてみます。
いつまで掛かるか分かりませんので、気長にお待ちください。
I’ll look into possible alternatives for the tuning meter in the future.
It may take some time, so I appreciate your patience.
