<h2>W&amp;H Alegra Contra-Angle Troubleshooting Guide</h2>

&nbsp;

Because Alegra runs off an external motor rather than its own drive, troubleshooting starts with a question most single-piece handpieces don&#39;t need: is this actually the Alegra head, or is it the motor or coupling driving it? Answering that first saves time on everything that follows.

&nbsp;

<h2>Warning Signs</h2>

&nbsp;

<ul>
	<li>
	Bur won&#39;t lock securely, or drops during use
	</li>
	<li>
	LED light dim, flickering, or off (LED G models)
	</li>
	<li>
	Noticeably reduced cutting power
	</li>
	<li>
	Unusual noise or vibration from the head
	</li>
	<li>
	Weak or misdirected spray
	</li>
</ul>

&nbsp;

<h2>Symptom, Cause &amp; First Step</h2>

&nbsp;

<table align="center" cellspacing="0" style="border-collapse:collapse; width:900px">
	<thead>
		<tr>
			<td style="background-color:#1a1a1a; border-bottom:#b9b9b9; border-left:#1a1a1a; border-right:#b9b9b9; border-top:#1a1a1a; width:217px">
			Warning Sign
			</td>
			<td style="background-color:#1a1a1a; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #b9b9b9; border-top:1px solid #1a1a1a; width:267px">
			Likely Cause
			</td>
			<td style="background-color:#1a1a1a; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #1a1a1a; border-top:1px solid #1a1a1a; width:267px">
			First Step
			</td>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:1px solid #1a1a1a; border-right:1px solid #b9b9b9; border-top:none; width:217px">
			Bur won&#39;t lock/drops
			</td>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #b9b9b9; border-top:none; width:267px">
			Chuck wear or debris
			</td>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #1a1a1a; border-top:none; width:267px">
			Clean chuck, re-test with a known-good bur
			</td>
		</tr>
		<tr>
			<td style="background-color:#f1f1ef; border-bottom:1px solid #b9b9b9; border-left:1px solid #1a1a1a; border-right:1px solid #b9b9b9; border-top:none; width:217px">
			LED dim or off
			</td>
			<td style="background-color:#f1f1ef; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #b9b9b9; border-top:none; width:267px">
			Low motor speed or generator fault
			</td>
			<td style="background-color:#f1f1ef; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #1a1a1a; border-top:none; width:267px">
			Confirm motor reaches ~9,000+ rpm first
			</td>
		</tr>
		<tr>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:1px solid #1a1a1a; border-right:1px solid #b9b9b9; border-top:none; width:217px">
			Reduced power
			</td>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #b9b9b9; border-top:none; width:267px">
			Motor/coupling issue, not the head
			</td>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #1a1a1a; border-top:none; width:267px">
			Test the head on a different motor if possible
			</td>
		</tr>
		<tr>
			<td style="background-color:#f1f1ef; border-bottom:1px solid #b9b9b9; border-left:1px solid #1a1a1a; border-right:1px solid #b9b9b9; border-top:none; width:217px">
			Noise or vibration
			</td>
			<td style="background-color:#f1f1ef; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #b9b9b9; border-top:none; width:267px">
			Internal gear or bearing wear
			</td>
			<td style="background-color:#f1f1ef; border-bottom:1px solid #b9b9b9; border-left:none; border-right:1px solid #1a1a1a; border-top:none; width:267px">
			Stop use; don&#39;t continue running it
			</td>
		</tr>
		<tr>
			<td style="background-color:white; border-bottom:1px solid #1a1a1a; border-left:1px solid #1a1a1a; border-right:1px solid #b9b9b9; border-top:none; width:217px">
			Weak/misdirected spray
			</td>
			<td style="background-color:white; border-bottom:1px solid #1a1a1a; border-left:none; border-right:1px solid #b9b9b9; border-top:none; width:267px">
			Blocked nozzle or worn seal
			</td>
			<td style="background-color:white; border-bottom:1px solid #1a1a1a; border-left:none; border-right:1px solid #1a1a1a; border-top:none; width:267px">
			Check nozzle and seal for buildup or wear
			</td>
		</tr>
	</tbody>
</table>

&nbsp;

<h2>User-Safe Checks You Can Do First</h2>

&nbsp;

<ol>
	<li>
	Confirm you&#39;re using the correct bur diameter for the model: 2.35mm CA burs for most Alegra contra-angles, 1.6mm FG burs specifically for WE-57 and WE-99.
	</li>
	<li>
	Clean the chuck mechanism and re-test bur retention with a pull test before assuming internal wear.
	</li>
	<li>
	For LED G models, verify your micromotor&#39;s actual speed output before suspecting the generator brightness is speed-dependent by design.
	</li>
	<li>
	Try the Alegra head on a different motor, if one&#39;s available, to isolate whether the fault is the head or the drive.&nbsp;
	</li>
</ol>

&nbsp;

<div class="fw fl mt10 mb15">
 <div class="w90p ml5p fl">
 <img class="blog_editor_image" alt="" height="535" src="https://s3.us-east-2.amazonaws.com/repair.dental/uploads/articles/dental_handpiece_performance_testing_.png" width="1000" />
 </div>
 
 <div class="fw fl">
 <div class="tc mt10 mb15 cgrey">
 
 dental handpiece performance testing 
 on
 <a href="https://repair.dental/repairguru/"
 class="cgrey b no_underline" 
 target="_blank"
 rel="noopener noreferrer"
 >
 Repair Guru
 </a>
 
 </div>
 </div>
 
 </div>

&nbsp;

<a href="https://repair.dental/print-shipping-label/handpiece-repair">Print Shipping Label</a>

&nbsp;

&nbsp;

<table align="center" cellspacing="0" style="border-collapse:collapse; width:900px">
	<tbody>
		<tr>
			<td style="background-color:#efefed; border-bottom:2px solid #1a1a1a; border-left:2px solid #1a1a1a; border-right:2px solid #1a1a1a; border-top:2px solid #1a1a1a; vertical-align:top">
			Stop Using It If...

			&nbsp;

			You notice unusual noise or vibration from the head, or bur retention can&#39;t be confirmed; these point reliably to internal wear that continued use will only worsen.

			&nbsp;

			A bur that occasionally feels loose is not a &quot;monitor it&quot; situation; inconsistent retention affects control during the procedure.
			</td>
		</tr>
	</tbody>
</table>

&nbsp;

<h2>When It Needs a Professional</h2>

&nbsp;

Chuck cleaning, bur selection, and isolating motor vs. head issues are all things a practice can do chairside. Internal gear wear, bearing damage, and generator faults on LED G models need a technician&#39;s tools to service properly, and W&amp;H&#39;s own materials note that some non-LED &quot;T&quot; model components are designed for user replacement, while others across the range are not.

&nbsp;

What Practices Are Saying

&nbsp;

<table align="center" cellspacing="0" style="border-collapse:collapse; width:900px">
	<tbody>
		<tr>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:4px solid #1a1a1a; border-right:1px solid #b9b9b9; border-top:1px solid #b9b9b9; vertical-align:top">
			★★★★★&nbsp; We chased a dim LED for weeks, assuming the handpiece was failing. It was our micromotor not hitting the speed the light needed.

			&nbsp;

			&mdash; Lead Dental Assistant, Pediatric Dental Practice
			</td>
		</tr>
	</tbody>
</table>

&nbsp;

<table align="center" cellspacing="0" style="border-collapse:collapse; width:900px">
	<tbody>
		<tr>
			<td style="background-color:white; border-bottom:1px solid #b9b9b9; border-left:4px solid #1a1a1a; border-right:1px solid #b9b9b9; border-top:1px solid #b9b9b9; vertical-align:top">
			★★★★★&nbsp; A quick chuck cleaning fixed what we thought was going to be a full repair on our WE-66. Worth trying before assuming the worst.

			&nbsp;

			&mdash; Office Manager, Solo General Practice
			</td>
		</tr>
	</tbody>
</table>

&nbsp;

<h2>FAQs</h2>

&nbsp;

My Alegra LED G light won&#39;t come on at all. Is the generator broken?

Not necessarily. Check that your motor is actually running and reaching sufficient speed first, since the LED+ light depends entirely on motor-generated power.

Is it normal for a push-button chuck to need occasional cleaning?

Yes, it&#39;s a wear point by design, and periodic cleaning is part of normal upkeep rather than a sign of a fault.

Can I tell if it&#39;s the Alegra head or the motor causing power loss?

Testing the head on a different motor, or a different head on your motor, is the fastest way to isolate which component is actually at fault.

<hr />
For more insights on professional dental equipment repair, please visit&nbsp;<a href="https://repair.dental/">Repair.Dental</a>&nbsp;or follow us on&nbsp;<a href="https://www.facebook.com/repair.dental">Facebook&nbsp;</a>&amp;&nbsp;<a href="https://www.instagram.com/repair.dental/">Instagram</a>.

Warning signs, causes, and safe checks for W&H Alegra contra-angle handpiece problems  and when to send it for repair.